September 5, 2022 Russia-Ukraine news

The United States Ambassador to Russia John Sullivan has left his post as the top US diplomat in Moscow and will retire, the embassy announced Sunday.

Sullivan departs amid a period of heightened tensions between the United States and Russia not seen in decades. He leaves after nearly three years as ambassador in Moscow, where he oversaw the embassy as it faced increasing restrictions imposed by the Russian government.

Sullivan concluded his tenure as US envoy and departed Moscow on Sunday, the US Embassy in Russia said in a press statement.

Elizabeth Rood would assume duties as Charge d’Affaires until the ambassador's successor arrives, according to the embassy.

On his last day as ambassador, Sullivan attended the public farewell ceremony for Soviet leader Mikhail Gorbachev on Saturday.

Speaking after the ceremony, Sullivan told CNN he had the honor to “represent the United States, President Biden, our government, the people of the United States to pay tribute to such a remarkable man, a great man, a statesman who changed the world, with his vision for peace, for transformation in his own country and in the world.”

The Ukrainian military appears to have taken control of the town of Vysokopillya in the southern Kherson region.

"There is a flag of Ukraine above the hospital on Gagarina Street, where my grandmother and grandfather's house was. And that's great," Dasha Zarivna, an advisor to the Head of the President of Ukraine's office Andrii Yermak, said.

One social media image shows Ukrainian soldiers raising a flag on the roof of a building, said to be in Vysokopillya. CNN cannot independently verify the location of the image.

A post on a pro-Russian Telegram channel said Sunday that Russian forces had "retreated in battle order from Vysokopillya (Beryslav district). The Armed Forces of Ukraine wanted to take them, surrounded by two pincers, from Olgyne and Potiomkyne."

Those are two neighboring settlements to the east and west of Vysokopillya, which had a population of about 5,000 before the war.

Some context: Ukrainian forces appear to have made limited territorial gains in Kherson to date. But the Institute for the Study of War said Saturday that according to Ukrainian officials, the offensive was "an intentionally methodical operation to degrade Russian forces and logistics, rather than one aimed at immediately recapturing large swathes of territory."

One Ukrainian official, Oleksiy Arestovych, told the Wall Street Journal on Saturday that the current goal of Ukrainian forces in the south is the “systemic grinding of Putin’s army, and Ukrainian troops are slowly and systematically uncovering and destroying Russia’s operational logistical supply system with artillery and precision weapon strikes."

Russian troops in Ukraine are still suffering from morale and discipline issues due to combat fatigue, high casualties and likely problems with their pay, the United Kingdom’s Ministry of Defense tweeted Sunday.

Russia’s military pays its troops a “modest” base salary, increased by a “complex variety of bonuses and allowances,” according to the UK’s Ministry of Defense.

CNN cannot independently verify these claims.

Some context: US and Western officials said in late August that Ukraine appears more evenly matched with Russian forces not only because of the advanced Western weaponry that Ukraine has been using, but also because the Ukrainians still have the advantage in terms of morale, unit cohesion, tactical acumen, and a superior ability to improvise on the fly.

By early August, Russia had suffered about 70-80,000 casualties, including troops killed and wounded, in its ongoing invasion, according to a Pentagon official.

Ukrainian officials have given upbeat assessments of the progress of the military's counteroffensive in the Kherson region, nearly one week after acknowledging the operation had begun.

There are indications that Ukrainian forces have made modest gains on the ground, but also of Russian counter-attacks in some areas. Much of the fighting is along the border of Kherson with the regions of Mykolaiv and Dnipropetrovsk.

Natalia Humeniuk, the spokeswoman for the Ukrainian military's southern command, said Ukraine was able to hit any routes the Russians could use to bring up reserves.

Ukrainian fire had caused "the destruction of command posts of many powerful units, on which the Russian leadership made a big bet. That is, these are already decapitated units," she said.

Humeniuk also said that new Russian attempts to build pontoon bridges across the river Dnipro to resupply their frontlines had been taken out.

She claimed that Ukraine's military operations would make it impossible for the Russians to stage referendums in areas they occupy. The resistance movement in the South was also "a serious factor that affects their [Russian] plans and actions, since it is both propaganda work and work to physically eliminate collaborators," she said.

In his daily video message on Saturday, President Volodymyr Zelensky also sounded an optimistic note about the battlefield. "

Ukrainian artillery was "doing everything to destroy the strike potential of the invaders," Zelensky added.

Some context: Ukrainian military officials have given few details on where progress is being made and to what extent. One axis of the counter-offensive appears to be south of the city of Kryvih Rih.

The Institute for the Study of War assessed Friday that the town of Kreshchenivka may now be in Ukrainian hands, because the Ukrainian General Staff had spoken of Russian airstrikes in the area. Remotely sensed fire data also suggests multiple explosions in the district over the last two days.

The West's biggest economies on Friday agreed to impose a price cap on Russian oil in an attempt to reduce Moscow's ability to fund its war in Ukraine without further stoking global inflation.

Finance ministers from the G7 group of countries — the United States, Japan, Canada, Germany, France, Italy and the United Kingdom — said they would ban the provision of "services which enable maritime transportation of Russian-origin crude oil and petroleum products globally" above the price cap. That could block insurance cover or finance for oil shipments.

But the measure still needs work and will be extremely complex to manage. The price at which Russian oil will be capped still needs to be hashed out. It would also need wider international support to be effective.

If the cap forces Russia to strike cheaper deals with trading partners by putting a ceiling on the price at which they can sell their products, it will still achieve its goals, a senior US Treasury Department official said on a call with reporters Friday.

Shortly after the G7 announcement, Russian state energy giant Gazprom said it would not resume deliveries through the Nord Stream 1 pipeline on Saturday as planned. The company cited an oil leak, and didn't give a timeline of when the shipments might resume.