The latest on the Ukraine-Russia crisis

President Sauli Niinistö of Finland told CNN Sunday that the world is “almost in a colder situation” than the actual Cold War era as tensions between the US and Moscow have reached a boiling point amid fears Russia will invade Ukraine.

President Biden has said he is convinced Russian President Vladimir Putin has decided to invade Ukraine, with his secretary of state, Antony Blinken, telling CNN on Sunday that the “playbook” for invasion is moving forward.

Recent shelling in eastern Ukraine and a vehicle blast in separatist-held Donbas has raised fears that Putin could be inciting violence to justify an invasion.

When asked if he thought an invasion would happen, Niinistö told CNN there were three possibilities.

“First one is that somehow they could settle the issue of eastern Ukraine, Minsk agreement and all that. I think it's far away. Then second option is that we will see a full-scale war,” he said. “And the third one, which is as bad, is that we see this kind of, like I described, two steps forward, one back, that is increasing tensions all the time. And the third one might at the moment, I would say, that might be the nearest one at least.”

President Sauli Niinistö of Finland said Sunday that he is not afraid his country could be next as Russian President Vladimir Putin increases military buildup around Ukraine.

"We are not afraid not at all,” Niinistö told CNN regarding his country which borders Russia to its north. “Actually, the situation in Finnish borderline and in whole Baltic Sea area is now quite peaceful. We are not afraid of Russian tanks, tanks suddenly crossing Finnish border.”

Acting US Ambassador to Ukraine Kristina Kvien expressed hope on Sunday that Vladimir Putin could ultimately decide not to invade Ukraine, despite President Biden's assessment the Russian leader has made up his mind to do so.

Kvien said it would be an "easy decision" for Putin to choose to take a path laid out by the US in communications with the Kremlin, and "we're hoping and urging him to do it."

The US diplomat said she agrees with Biden and other top administration officials' determination that Putin has made up his mind and is "likely" to move in on Ukraine, but that doesn't mean his decision is final.

"It doesn't mean President Putin can't change his mind. But I do think that right now, he's moving towards a large-scale invasion," she said.

Kvien noted the refugee crisis that could occur in Europe after an invasion of Ukraine, saying it would be "destabilizing."

Secretary of State Antony Blinken said on CNN that he's planning to meet with Russian Foreign Minister Sergey Lavrov this week "provided Russia doesn't invade Ukraine in the interim."

He noted that the US "put on the table a number of ideas that we can pursue that would strengthen security" for Russia, the United States, and the rest of Europe.

"That's the conversation I welcome having with Foreign Minister Lavrov. It depends entirely on if Russia invades or not," Blinken said.

Secretary of State Antony Blinken told CNN that the US is prepared to do everything it can to prevent Russia from invading Ukraine

Blinken reiterated President Biden's concerns that Russia has already set invasion plans in motion.

US Secretary of State Antony Blinken said he was concerned about reports that troops from Russia and Belarus will continue joint military exercises past their planned end date as the thread of a Russian invasion looms large.

Blinken continued: "We've seen that over the last few days. Now they're justifying the continuation of exercises, exercises in quotation marks that they said would end now. The continuation indefinitely of those, quote, unquote, exercises, on the situation in eastern Ukraine, a situation that they created by continuing to ramp up tensions."

Blinken noted that Russia has been "escalating the forces they have across Ukraine's borders over the last months, from 50,000 forces to 100,000 to now more than 150,000." 

"So all of this along with the false flag operations we've seen unfold over the weekend tells us the playbook we laid out is moving forward," he said.

As Ukrainian authorities reported further ceasefire violations in the east of the country and top Western officials, including the US Vice President Kamala Harris and British Prime Minister Boris Johnson, warned about an impending conflict, people in Kyiv weren't giving up on leisure.

Across the Ukrainian capital, families flocked to the parks and playgrounds on Sunday, enjoying the winter sunshine and blue skies. 

This is not a city that looks like it's on the brink of a conflict. Under the Motherland Monument, a 102-meter tall statue of a woman with a shield and a sword that towers over the country’s war museum, children were having great fun climbing up and down the tanks on display there. 

Across the river, in Dniprovsʹkyy Park, scores of people were spending their Sunday morning running, cycling and in-line skating. Nearby, on the sandy bank of the Dnieper river, children were happily digging in the sand, watching the ducks swim by. But the sense of pride and resolve, heightened in recent months amid the growing tension, remains ever-present. 

On the world-famous Maidan square, the site of the 2014 bloody protests, huge flags are still on display following Wednesday’s Day of Unity, a national holiday spontaneously declared by the Ukrainian President Volodymyr Zelensky.

On a hill above the square, photographs of those who died during the protests are on permanent display.

The events of 2014 are known here as the “Revolution of Dignity” and those who died during them are referred to as the “Heavenly Hundred.” On Sunday, dozens of people gathered by the memorial wall, lighting candles, laying flowers and decorating the monument with fresh blue and yellow ribbons which are on display everywhere in the city.

French President Emmanuel Macron called both his Russian and Ukrainian counterparts on Sunday morning in a “last-ditch effort to avert a Russian invasion of Ukraine,” the Élysée Palace said in a statement.

Macron spoke with Ukraine’s Volodymyr Zelensky for 30 minutes, right after a long phone conversation with Russian President Vladimir Putin, according to the French presidency.

“The phone conversation with President Putin lasted 1 hour 45 minutes,” the Élysée Palace said.

The calls come a day after the French President previously spoke with Zelensky.

An Élysée Palace source had previously told CNN that Paris hoped to “construct a useful roadmap for the coming days.”

Russian President Vladimir Putin "has every reason" to see Ukrainian President Volodymyr Zelensky as unwilling to implements the Minsk agreements, Russian presidential spokesperson Dmitry Peskov said in comments Sunday on Russian state television. 

Peskov also suggested the Kremlin was prepared to disclose confidential discussions of high-level talks with other world leaders to counter what he described as deliberate and misleading leaks by foreign officials. 

"I hope that we will not live in a world where we have to read out the transcripts of the closed part of the presidents' talks," Peskov said. "But when it is necessary to prove the correctness of our president, we can and will do anything."

Some history: In early 2014, mass protests in the capital Kyiv known as Euromaidan forced out a Russia-friendly president after he refused to sign an EU association agreement.

Russia responded by annexing the Ukrainian peninsula of Crimea and fomenting a separatist rebellion in Ukraine's east, which seized control of part of the Donbas region. 

A rare meeting between Russian, Ukrainian, German and French leaders in February 2015 sought to bring peace to areas of Ukraine that had been taken over by pro-Russian separatists the year before.

Those areas, in Ukraine's Donbas region, became known as the Luhansk People's Republic (LPR) and the Donetsk People's Republic (DPR). The Ukrainian government in Kyiv asserted the two regions were in effect Russian-occupied.

The talks also aimed to work towards a political settlement for the region.

The result, Minsk II, was signed by representatives of Russia, Ukraine, the separatist leaders and the Organization for Security and Co-operation in Europe (OSCE). It was subsequently endorsed by a UN Security Council resolution.

After Minsk II was signed, the worst of the fighting stopped, and OSCE monitors moved in. To this day, the OSCE patrols the frontlines and reports ceasefire violations along the border. However, there is much less fighting and fewer casualties than in 2014-15. From that perspective, the agreement was, at least, partly fulfilled.

Even so, nearly 14,000 people have died in the conflict, and there are 1.5 million people internally displaced in Ukraine, according to the Ukrainian government.

CNN's Eliza Mackintosh and Tim Lister contributed reporting to this post.