Russia has increased its presence along the Ukrainian border by as many as 7,000 troops in the last few days, with some arriving Wednesday, a senior White House official told ABC News.

The assessment comes a day after the Russian government said it has started to withdraw some troops from near Ukraine's borders.

The official didn't comment on the total number of Russian forces currently along the border.

President Joe Biden said Tuesday that Russia has "more than 150,000 troops encircling Ukraine and Belarus and along Ukraine's border." It's unclear if that number includes any of the new troops cited by the official.

Private satellite imaging company Maxar on Wednesday released over two dozen new images from the last 48 hours that continue to show Russia's heightened military activity in Belarus, Crimea and western Russia.

They include images that show a new 20-strong attack helicopter unit deployed in Belarus, a field hospital in Belarus and a pontoon bridge that has appeared across a river in Belarus, four miles from Ukraine’s border.

At least three of the images indicate some troops have departed or are preparing to depart, according to Maxar, though it's unclear where the troops are going.

-ABC News' Mary Bruce and Patrick Reevell

President Joe Biden had a secure call Wednesday afternoon with German Chancellor Scholz, according to the White House, ahead of Secretary of State Antony Blinken traveling to Germany on Thursday for the Munich Security Conference.

The two leaders "reaffirmed their commitment to Ukraine’s sovereignty and territorial integrity" and "underscored the importance of continued transatlantic coordination on diplomacy and deterrence measures," the White House said.

Scholz visited the Kremlin and met with Russian President Vladimir Putin on Wednesday, after meeting with Ukrainian President Volodymyr Zelenskyy in Kyiv on Monday. The German chancellor has said that war is "unimaginable" and shouldn't be an option since Ukraine has not formally requested to join NATO, as Russia demands it be barred from doing so.

"That is why it is somewhat peculiar to observe that the Russian government is making something that is practically not on the agenda the subject of major political problems," Scholz said earlier this week.

"That is, after all, the challenge we are actually facing. That something that is not at all an issue now is being made an issue," he said.

British Army Lt. Gen. James Hockenhull, chief of defense intelligence, said Wednesday that the U.K. has also not seen evidence that Russia is withdrawing substantial forces from near Ukraine, matching comments from NATO and U.S. officials.

"We have not seen evidence that Russia has withdrawn forces from Ukraine’s borders. Contrary to their claims, Russia continues to build up military capabilities near Ukraine," Hockenhull said in a rare public statement.

"This includes sightings of additional armoured vehicles, helicopters and a field hospital moving towards Ukraine’s borders. Russia has the military mass in place to conduct an invasion of Ukraine," he said.

Russian units that are supposedly pulling back appear to actually be returning to their home bases that are already located next to Ukraine. Security analysts say that Russia appears to simply be shuffling its forces for the time being, while more continue to arrive.

France's Foreign Minister Jean Yves Le Drian in the French Senate Wednesday also said, for now, they are unable to say whether Russian troops are withdrawing or rotating but that Russia has all the elements in place for an attack.

-ABC News' Matt Seyler, Patrick Reevell and Anna Rabe

State Department spokesperson Ned Price said Russia was not only not withdrawing, but also moving troops into fighting positions at a briefing on Wednesday, as ABC News first reported Tuesday.

"To be very, very clear, we have not seen that. In fact, we have seen the opposite. In recent weeks and even in recent days, more Russian forces, not fewer, are at the border -- and they are moving, concerningly, into fighting positions," Price said. "This is cause for profound concern."

Price also accused Russian officials and Russian media of "plant[ing] numerous stories in the press, any one of which could be elevated as pretext for an invasion" which, he said, "could happen, we are concerned, at any time, and the world should be ready for it."

The U.S. is "particularly concerned" by Russian President Vladimir Putin and others' claims of "genocide" in the Donbas, Price said, as well as false claims of Ukrainian attacks on Russian-led separatists in eastern Ukraine, U.S. or NATO action against Russia, U.S. and Ukraine developing biological and chemical weapons, or the West backing guerrillas in eastern Ukraine.

"These are false narratives that Russia is developing for use as a pretext for military action against Ukraine," Price added.

While Feb. 16 has almost come and gone in Kyiv, Price rejected that it meant U.S. intelligence was wrong about a possible Russian invasion -- saying both that the U.S. never said specifically that Feb. 16 would be the date of an attack and that Putin still have the capabilities in place to strike at any moment.

"Our concern has not diminished an iota, and in fact, our concern continues to grow given that we have yet to see de-escalation, and given that, in the absence of de-escalation, we've actually seen escalation," he said -- now saying it's possible Russia attacks after the Olympics, too.

-ABC News' Conor Finnegan