NATO warns Russia still building up troops, as Ukraine holds defiant national holiday

LVIV, Ukraine -- NATO’s secretary general warned that Russia appears to still be increasing the number of its troops near Ukraine, despite Moscow announcing it has begun withdrawing some military units from the border.

Ukraine on Wednesday held a nationwide “Unity Day," hanging flags and holding ceremonies to sing the nation's anthem on the day that U.S. officials had said a Russian invasion could take place. President Volodymyr Zelenskyy instituted the public holiday in an apparent signal of defiance that also indicated Ukrainian skepticism that an attack would take place.

Russian officials, meanwhile, mocked claims that the attack would materialize Wednesday, saying it illustrated Western “hysteria” around Russia’s buildup of troops close to Ukraine. Russia’s military a day earlier said some of its troops have started to withdraw after completing “exercises” and on Wednesday said that process was continuing, releasing new video showing a trainload of armored vehicles rolling across a bridge from Crimea to Russia.

But NATO’s secretary general Jens Stoltenberg said that despite the few videos released by Russia, the alliance so far sees no evidence of actual withdrawal and that more troops have continued to arrive.

“So far we have not seen any de-escalation on the ground. On the contrary, it appears that Russia continues the military buildup," Stoltenberg told reporters before a two-day meeting of NATO’s 30 defense ministers in Brussels.

“We are, of course, monitoring very closely what Russia does in and around Ukraine. What we see is that they have increased the number of troops and more troops are on their way and so, so far, no de-escalation,” he said.

But Stoltenberg said the alliance still hoped Russia would choose a diplomatic way out of the crisis, noting recent statements from President Vladimir Putin expressing a readiness to engage with the West.

“Of course, we hear all the messages about diplomacy and we are ready to engage in diplomatic efforts with Russia," Stoltenberg said.

Russia’s military said units from its western and southern military districts, that have amassed thousands of troops near Ukraine, have begun returning to their bases. The defense ministry on Wednesday said the western military district units had completed loading their tanks onto transports and were now beginning a “1000 kilometer” journey back to their home base.

Russia is continuing to hold huge exercises in neighboring Belarus and in the Black Sea, which are due to run until the end of this week.

Western and Ukrainian officials, as well as independent military analysts have expressed skepticism that the announced moves reflect a true pull-back, noting that previously announced withdrawals have amounted to little more than shuffling forces around.

U.S. officials also said they have not seen a real withdrawal.

"On the contrary, we continue to see forces, especially forces in the vanguard of any renewed aggression against Ukraine, continuing to be at the border, to mass at the border," Secretary of State Anthony Blinken told ABC’s George Stephanopoulos on "Good Morning America" Wednesday.

Russia has amassed an estimated 150,000 troops on three sides of Ukraine, a presence that includes long-range artillery, advanced aircraft and dozens of attack helicopters. U.S. officials have warned in recent days that some of the troops appear to be moving into "firing positions".

Satellite photographs from a private company and videos spotted on social media by open source researchers appear to show that for now Russia has continued to move forces closer to the border with Ukraine. A large number of cellphone videos have appeared on TikTok that seem to show convoys of tanks and armored vehicles moving in the Belgorod region that borders Ukraine.

The Russian state newspaper Izvestia cited defense ministry sources that the units re-basing were the western district’s 3rd Motor Rifle Division and the southern district's 42nd Guards and 150th Motorized-Rifle Division. But analysts said that the units' home base are located close to Ukraine in any case. The 3rd Motor Rifle Division is based in the town of Boguchar, only about 60 miles from the border. It means the units rather than pulling back from the border are simply moving to a different location along the border.

Belarus' foreign minister Vladimir Makey said at a press conference on Wednesday that all Russian troops would leave his country after the joint drills end February 20.

U.S. officials continue to believe it is likely Russia will launch a large-scale invasion, potentially as early as this week, although they don't believe Putin has made a final decision yet. ABC News learned that U.S. officials had briefed allies that Wednesday could be the day of the attack because they had information Putin has ordered his military to be ready to go from that day.

The U.S. assesses that Russia now has all the necessary forces in place to launch a major attack if Putin chooses. It believes such an attack would not be limited to eastern Ukraine but would target the capital Kyiv, aiming to decapitate the government in a lightning strike planned to be over within 72 hours. The operation would be preceded by large-scale cyber attacks and aerial bombardments against critical infrastructure, before special forces enter Kyiv to target Ukraine's leadership. Russian forces in neighboring Belarus would sweep in from the north, according to the U.S. assessment.

A cyber attack hit the website of Ukraine’s defense ministry and two of its largest state banks on Tuesday night. The cyber defense department of Ukraine’s national security service said the DDoS attack was very large, but the damage appeared limited, it said due to preparations Ukraine had taken in recent weeks. After some disruption in online payments, the two banks, Privat Bank and the State Savings Bank, said their systems were working again. The security service said the U.S. was assisting Ukraine in protecting itself against the attack.

Ukraine’s government has appeared more skeptical of the invasion risk, with senior officials saying they did not see signs Russia was preparing to attack Wednesday.

President Zelenskyy inspected military exercises in the Rivne region near Belarus, wearing army fatigues. In an address filmed selfie-style on his phone earlier Wednesday, he told Ukrainians, “Our shared desire to live unites us, to live together in peace. We are in Ukraine and no one can defend our home like we can.”

In Lviv, the largest city in western Ukraine, hundreds of cadets at a local military academy gathered around a towering flag pole on Wednesday morning for a ceremony, where they sang the national anthem, which begins “Ukraine is not dead yet.”