US and NATO officials say they have not seen a major withdrawal of Russian troops from Ukraine's borders, despite President Vladimir Putin's announcement this week that Russian military officials have ordered some troops to return to Ukraine.

"Unfortunately, there is a gap between what Russia is saying and what it is doing, and what we are seeing is not significant resistance," Secretary of State Antony Blinken said in an interview with ABC's Good Morning America on Wednesday.

A senior government official told reporters at a briefing on Wednesday that Russia's claim that it was withdrawing troops from the border was "false."

In fact, we have now confirmed that in recent days Russia has increased its troop presence along the Ukrainian border by up to 7,000 troops, some of whom just arrived today,” the official said.

The number of Russian troops surrounding Ukraine's borders on three sides has risen to 150,000, President Biden said Tuesday.

Commercial satellite imagery has shown their numbers increasing in recent weeks, including large deployments of attack aircraft in locations near the Ukrainian border. In Belarus, north of Ukraine, around 30,000 Russian soldiers are taking part in joint military exercises.

Late last week, US officials dramatically escalated warnings about the situation in Ukraine, urging Americans to leave the country as soon as possible ahead of an invasion that White House National Security Advisor Jake Sullivan says "it could happen very soon".

On condition of anonymity, officials said Russia's military preparations for a full-scale invasion were complete and an invasion was possible at any time this week.

That assessment hasn't changed, Blinken said on Wednesday.

“President Putin has created the ability to act at very short notice. You can pull the trigger. I could do it today, I could do it tomorrow, I could do it next week," Blinken said.

Putin has repeatedly said that Russia has no intention of attacking Ukraine. At a press conference on Tuesday with Chancellor Olaf Scholz, Putin said Russia wanted to reach an agreement "through diplomatic channels."

Putin added that the Russian military leadership had decided to "withdraw part of the troops".

But outside Russia, officials said they would reserve judgment until they see evidence of such a reduction. "We've had other cases where they made similar claims, and indeed the facts on the ground have shown the opposite," Julie Smith, the US ambassador to NATO, said Wednesday.

NATO sees no signs of a Russian withdrawal
NATO, the defensive alliance that has long drawn the wrath of Russia, has come to similar conclusions as US officials.

"So far we haven't seen any signs of a de-escalation on the ground. There is no withdrawal of troops or equipment," said Secretary General Jens Stoltenberg on Wednesday at a meeting of NATO defense ministers in Brussels. "What we see today is that Russia has a massive invasion force ready to strike."

NATO is considering setting up new combat units in Central and Eastern Europe, Stoltenberg said. The alliance has had a stronger presence in Eastern Europe since the Russian invasion of Crimea, including battlegroups based in each of the three Baltic states and Poland. The United States oversees the Poland-based group.

Stoltenberg did not say exactly where the new combat groups would be based, but a likely location is Romania, which borders western Ukraine. US Secretary of Defense Lloyd Austin is attending this week's meetings.