Russia expanded its offensive to western Ukraine on Sunday, firing missiles near the city of Lviv and hitting a large military base close to the Polish border, reportedly killing dozens of people and drawing the war closer to the borders of a NATO country. The attack came the day after the Kremlin threatened to attack Western weapons shipments to Ukraine. As the invasion runs into its third week, the northwest city of Lviv has largely been spared from Russia’s relentless bombardment. The picturesque city has instead become ground zero for displaced Ukrainians. Hundreds of thousands of them have flooded into the city in search of relative safety, with many using it as a stopping point before making their way to the Polish border about 43 miles (70 kilometers) away. But Russia’s war is moving closer to the cultural hub. Russian forces fired more than 30 missiles at Yavoriv military training ground on Sunday, according to Lviv’s military administration. Located between Lviv and the Polish border, the military base has held joint drills with NATO and Western military personnel, including the United States. A witness, who was on the base when the strike happened, told CNN of hearing a “sudden clap” from a bomb shelter, adding that the explosion craters were 10 meters deep and there are fears people are under the rubble. Local authorities say 35 people were killed and 134 injured at the military base, in what Ukraine’s Minister of Defence Oleksii Reznikov described as a “terrorist attack” on peace and security “near the EU-NATO border.” There were no reports of foreign nationals among the casualties so far, say Ukraine defense officials. The strike came the day after Russia launched a missile attack in the northeastern city of Lutsk, only 70 miles from the Polish border. Ukrainian President Volodymyr Zelensky said Sunday that it was only a matter of time before Russia’s military assault on Ukraine expanded to members of NATO – unless the alliance installs a no-fly zone in Ukraine. “Last year, I made a clear warning to NATO leaders that if there were no tough preventive sanctions against Russia, it would start a war,” Zelensky said in a video address Sunday posted to his Facebook page. “Now, I repeat again, if you do not close our sky, it is only a matter of time before Russian missiles fall on your territory. NATO territory. On the homes of citizens of NATO countries.” US national security adviser Jake Sullivan told CNN that the strikes on Lviv were a sign that the war was not going to plan. Russian President Vladimir Putin “is frustrated by the fact that his forces are not making the kind of progress that he thought that they would make against major cities, including Kyiv, that he is expanding the number of targets, that he is lashing out, and that he is trying to cause damage in every part of the country,” Sullivan said. A senior US official told CNN Sunday that Russia has asked China for military assistance in Ukraine, including drones. Potential assistance from the Chinese would be a significant development in Russia’s invasion, and could upend the hold Ukrainian forces still have in the country. When asked by CNN about reports of Russia’s request for military aid, Liu Pengyu, spokesperson for the Chinese embassy in the US, said in a statement, “I’ve never heard of that.” As attacks on civilian areas continued throughout the weekend, a new round of Russian-Ukrainian talks has been set for Monday. Zelensky alluded to the talks in his remarks Sunday, saying his country’s delegation “has a clear task – to do everything to ensure a meeting of the presidents. The meeting that I am sure people are waiting for.” US President Joe Biden spoke with French President Emmanuel Macron on Sunday evening, according to a White House official. Macron had spoken to Putin on Saturday in a joint call with German Chancellor Olaf Scholz. American journalist killed in Ukraine Heavy fighting continued Sunday, with Britain’s Ministry of Defense saying Russia was attempting to “envelop” Ukrainian forces in the east of the country as it advanced from Crimea westwards towards Odessa. Russian troops continue to focus on the capital Kyiv. Ramzan Kadyrov, the pro-Kremlin leader of Russia’s Chechnya region, reportedly told Russian soldiers outside of Kyiv that the key task is to seize the capital, Russian state news network Russia 24 reported on Sunday. Amid a growing civilian toll in Ukraine, American journalist Brent Renaud, 50, was killed by Russian forces in Irpin, on the outskirts of Kyiv, according to social media posts by Kyiv region police. Two other journalists were wounded by Russian troops, the police added. Renaud “paid with his life for attempting to expose the insidiousness, cruelty, and ruthlessness of the aggressor,” an adviser to Ukraine’s interior minister, Anton Gerashchenko, said in a statement on Telegram. The US State Department confirmed Renaud’s death on Sunday. “We are horrified that journalists and filmmakers—noncombatants—have been killed and injured in Ukraine by Kremlin forces,” department spokesman Ned Price said on Twitter. “This is yet another gruesome example of the Kremlin’s indiscriminate actions.” Social media footage has emerged of a journalist identified as Juan Arredondo, a filmmaker and visual journalist who is also an adjunct professor at Columbia Journalism School, at Okhmatdyt hospital in Kyiv, in which he describes being shot at by Russian forces while driving through a checkpoint in Irpin on the way to film refugees leaving the city. The exact circumstances of the attack against the two journalists are yet to be determined. TIME released a statement Sunday saying Renaud was in the region working on a TIME Studios project on the global refugee crisis. “We are devastated by the loss of Brent Renaud. As an award-winning filmmaker and journalist, Brent tackled the toughest stories around the world often alongside his brother Craig Renaud,” TIME Editor in Chief and CEO Edward Felsenthal and President and COO Ian Orefice in the statement. Ukrainians take to the streets to protest Ukrainians continue to protest Russian occupation. The southern city of Kherson, which is occupied by Russian forces, saw the biggest protest since the invasion on Sunday. Hundreds of demonstrators flocked to the streets to protest against suspected Russian plans to turn the southern Ukrainian oblast into a breakaway republic. Waving Ukrainian flags, the protesters chanted anti-Russian slogans, filled with expletives about Putin, according to videographer Artem Ivanov, who is on the ground in Kherson. Ihor Kolykhaiev, the mayor of Kherson, said in a video posted on Facebook Sunday that mass protests show “Kherson is Ukraine” and insisted that he retains administrative control of the city. But the mayor also said that the city had been cut off from humanitarian aid and was running out of resources. He said that the city “can’t receive a humanitarian cargo here, food is finishing in the stores, we are running out of gas, we only have diesel oil left at the gas stations. We are running out of the medications and insulin.” “Our main weapon is unity,” he added. In recent days, at least one Kherson regional council official warned that occupation forces were laying the groundwork for the “Kherson People’s Republic.” If true, the move would mirror Moscow’s establishment of two Russian-backed breakaway states in Ukraine’s eastern Donbas region. Putin recognized the independence of those two territories in the days leading up to Russia’s full-scale invasion of Ukraine as part of his pretext to launch an assault on the country. School demolished by Russian strike Russia’s air offensive on Sunday also bore down on heavily populated areas around the country. Nine people were killed in a Russian bombardment in Mykolaiv Sunday, local officials said. The strategic southern city has resisted Russian occupation and impeded an apparent push towards the major port of Odessa to the west. A school in the village of Zelenogai, about 10 miles (16 kilometers) east of Mykolaiv, was demolished by a Russian military strike, Mykolaiv regional administrator Vitali Kim said. Kim said that the military strike left several people either dead or in critical condition. “Some people got under the rubble and we are evacuating them,” Kim said. Missiles also destroyed an airport in the western Ukrainian city of Ivano-Frankivsk, while the northern city of Chernihiv was struck for the third night in a row, hitting a high-rise building, the regional head, Vyacheslav Chaus, said. In the eastern region of Luhansk, much of which is now occupied by Russian forces, the head of the regional administration, Serhiy Haidai, said there had been “massive shelling” of several towns, including Kreminna and Rubizhne, which had prevented buses from leaving with civilians. The Ukrainian military thwarted an attempt by Russian military vehicles to cross the Irpin River on a pontoon bridge near Hostomel, a new satellite image from Maxar Technologies shows. The bridge first appeared in satellite imagery from Maxar on March 10, appearing to have been destroyed. An additional photo, published on social media on March 13, also shows the pontoon bridge destroyed, in addition to nearby Russian military vehicles. Ukrainian forces in Kyiv’s suburb of Irpin have so far repelled the Russian forces’ attempted advance towards the Ukrainian capital city. With the main bridge crossing the Irpin River having been destroyed by the Ukrainians, the river poses a significant obstacle for the Russian military. Also on Sunday, Ukraine’s National Energy Company Ukrenergo completed repair work and resumed power supply to the Chernobyl nuclear power plant, the company announced. The plant’s electrical system was damaged during a Russian attack on March 9. Later on Sunday, the International Atomic Energy Agency said in a statement that the staff at the Chernobyl nuclear power plant are so tired they have stopped carrying out the repair and maintenance of safety-related equipment. As the devastation mounts, Zelensky said the key task Sunday is to get the humanitarian convoy that is traveling towards the besieged city of Mariupol to its destination. Mariupol has been under siege for more than a week. Much of the city is without power and water. Mariupol’s city administration confirmed Sunday night that the convoy was still stuck some 50 miles to the west. As the city waits, officials said it had suffered 22 bombing attacks in the last 24 hours and “to date, 2,187 Mariupol residents have died from attacks by Russia.” Ukraine’s Deputy Prime Minister Iryna Vereshchuk said that nine of the 14 evacuation routes declared Sunday had allowed civilians to escape fighting. About 3,950 people were rescued in the Kyiv region and 1,600 were able to escape from the Luhansk region in the east of the country, according to Vereshchuk. “The city of Mariupol was subjected to shelling and aerial bombardment all day long,” Vereshchuk said. “The humanitarian cargo remained blocked in the city of Berdyansk halfway to the occupied city.” New round of talks Ukrainian presidential adviser Mykhailo Podoliak said Sunday that the next round of Russian-Ukrainian talks will take place on Monday, via video link. “Again. Negotiations go non-stop in the format of video conferences,” Podoliak said on Twitter. “Working groups are constantly functioning. A large number of issues require constant attention.” Kremlin spokesman Dmitry Peskov told Russian state news agency RIA earlier on Sunday that the talks would continue on Monday. Podoliak said earlier Sunday that he believed that talks in the next few days will “achieve concrete results.” “Our proposals are on the table. They are very tough. Among them, the withdrawal of troops, the ceasefire,” Podoliak said in a video posted on Twitter. This comes after Leonid Slutsky, a Russian delegation member for talks with Ukraine, said “significant progress” has been made in negotiations with the Ukrainian delegation since the beginning of talks, Russian state news agency RIA reports. Talks between Ukraine’s and Russia’s top diplomats last week in Turkey, however, yielded no discernible progress. In Russia, authorities continue to violently repress all dissent. Riot police arrested more than 658 people in 35 Russian cities on Sunday, as the number of those detained grows, according to an independent human rights group, OVD-Info. Images of brutal arrests have flooded social media showing people dragged off the streets by Russia’s riot police. OVD-info also reported cases of house searches of human rights activists, police officers stopping people on the street to check through bags, as well as phone records. According to the monitoring group, more than 5,000 people have been arrested across Russia for participating in anti-war protests since last weekend and over 14,633 protesters have been detained in dozens of cities since the start of the invasion on February 24.