Russia-Ukraine updates: US to ban Russian carriers from its airspace

Tensions around the Russian-controlled separatist areas in eastern Ukraine's Donbas region remained high on Thursday night, with reports of more shelling.

Sporadic firing from the separatist side continued to hit the Ukrainian government-controlled village of Stanytsia Luhanska, setting two homes on fire, local police told ABC News. Earlier Thursday, separatist shelling struck a kindergarten in the village, injuring two teachers.

The escalation comes amid concerns from Western officials that Russia and its separatist proxies may be laying the groundwork for a pretext for a possible Russian intervention by accusing Ukraine of preparing to launch an offensive.

Valery Zaluzhny, the head of Ukraine’s Armed Forces, warned in a statement Thursday night that the military has information the separatist forces are planning to evacuate several villages near the front line, possibly ahead of a planned escalation in firing.

Zaluzhny also accused the Russian-backed forces of firing deliberately onto civilian infrastructure and accused Russia and the separatists of using propaganda and disinformation to claim Ukraine is shelling civilians.

He said Ukraine is not planning any offensive operations and is observing a ceasefire.

There was dramatically more shelling Thursday than usual, according to monitoring by the Organization for Security and Cooperation in Europe. Ukraine accused the separatists of violating the ceasefire 47 times, including mainly using large-caliber weapons banned from the front line. 

Russian officials continued to claim Thursday that some Russian forces are returning to their home bases and accused the U.S., along with the U.K., Canada and the Baltic nations, of using claims of Russian aggression as a pretext to arm Ukraine.

-ABC News' Patrick Reevell and Fidel Pavlenko

Secretary of Defense Lloyd Austin, at NATO headquarters in Brussels Thursday, said the U.S. has evidence of Russia stocking up on blood supplies and military forces nearing the border as officials believe Russia will launch an invasion of Ukraine within days. 

"We see some of those troops inch closer to that border. We see them fly in more combat and support aircraft. We see them sharpen their readiness in the Black Sea. We even see them stocking up their blood support supplies," Austin told world leaders.

"You know, I was a soldier myself not that long ago, and I know firsthand that you don't do these sorts of things, for no reason. And you certainly don't do them if you're getting ready to pack up and go home," he added. 

President Joe Biden and Secretary of State Antony Blinken also warned Thursday that, despite claims of pulling back, Russia appears to be ready to invade at any moment.

-ABC News' Matt Seyler

As Secretary of State Antony Blinken told the U.N. Security Council Thursday the U.S. believes Russia plans to "manufacture a pretext" for an invasion of Ukraine, such as with false claims of violence by Ukrainians in the country, the U.S. embassy in Kyiv explicitly blamed Russia for the overnight shelling in Donbas in a series of tweets. 

"Russia's shelling of Stanytsia Luhanska in Ukrainian government-controlled territory in Donbas hit a kindergarten, injured two teachers, and knocked out power in the village," the Twitter statement said. "The aggressor in Donbas is clear - Russia."

The statement continued: "This attack, as with so many others, is a heinous Russian violation of the Minsk Agreements and again demonstrates Russia's disregard for Ukrainian civilians on both sides of the line of contact."

Ukraine has also blamed Russia-backed separatist forces for shelling the village controlled by Ukrainian government troops and hitting a kindergarten there early Thursday.

Russia-backed separatist authorities in eastern Ukraine have, in turn, accused the Ukrainian military of preparing for a full-scale offensive.

Blinken told world leaders to expect this and more, "claims of mass graves, staged drone strikes, a terrorist bombing, or chemical or biological weapons -- even the use of those dangerous weapons," and said that "Russian media have already begun to spread these false alarms."

The Russian mission to the U.N. circulated a letter overnight that it said included an investigation of atrocities committed by the Ukrainian government, alleging that Ukraine committed war crimes over the last eight years in the Donbas -- alarming U.S. officials, who believe it may be part of the false pretext for a Russian invasion they've publicly warned about for weeks.

"It's hard to draw any conclusion other than Russia plans to use today's U.N. Security Council meeting as part of an attempt to establish a pretext for a potential invasion, building upon disinformation and incendiary statements we've seen over recent weeks," a senior administration official told reporters Thursday morning. "Each of these allegations are categorically false."

As U.S. officials expected, Russia's Deputy Foreign Minister Sergey Vershinin, speaking ahead of Blinken at the U.N., blamed Ukraine for failing to implement the Minsk agreements, he said, and accusing it of atrocities against civilians in its eastern provinces.

-ABC News' Matt Seyler and Conor Finnegan

Secretary of State Antony Blinken closed his remarks to the U.N. Security Council meeting by challenging the Russian Federation to "announce today -- with no qualification of equivocation or deflection -- that Russia will not invade Ukraine, stated clearly stated plainly, to the world."

"And then demonstrate it by sending your troops, your tanks, your planes back to their various can hangars and sending your diplomats to the negotiating table," he added.

Blinken laid out how the U.S. believes Russia will attack Ukraine -- but said he would welcome being wrong and for Russia to withdraw.

"Now, I'm mindful that some have called into question our information, recalling previous instances where intelligence ultimately did not bear out," he said, apparently referring to a similar address then-Secretary of State Colin Powell famously made to the Security Council presenting U.S. intelligence to justify the Iraq War. "But let me be clear, I am here today not to start a war, but to prevent one," he said, citing allies that agree with U.S. assessments.

"If Russia doesn't invade Ukraine, then we will be relieved that Russia changed course and proved our predictions wrong. That would be a far better outcome in the course we're currently on. And we'll gladly accept any criticism that anyone directs at us," Blinken said. 

He continued, "Russia can still make if there's any truth to his claim that is committed to diplomacy. Diplomacy is the only responsible way to resolve this crisis"

Blinken also said that he sent a letter to Russia's Foreign Minister Sergei Lavrov earlier Thursday proposing that they meet next week in Europe following their talks in recent weeks "to discuss the steps that we can take to resolve this crisis without conflict" and that U.S. is also proposing meetings at the NATO Russia Council and the OSC Permanent Council. 

"These meetings can pave the way for a summit with key leaders in the context of de-escalation to reach understandings on our mutual security concerns," he added.