President Joe Biden asserted Tuesday that he has no intention of sending U.S. troops into Ukraine, as fears linger about a possible Russian invasion of the eastern European country.

Biden made the remark to reporters during a stop at a Washington, D.C., gift store. The Pentagon announced Monday it has placed 8,500 troops on “heightened alert” for possible deployment to eastern Europe to aid a NATO response force “or if other situations develop.”

Last week, Biden predicted Russia, which has amassed 100,000 troops near the Ukrainian border, will invade Ukraine. But on Tuesday, he seemed less sure, saying, “It’s a little bit like reading tea leaves.”

“Ordinarily, if it were a different leader, the fact that he (Russian President Vladimir Putin) continues to build forces along Ukraine’s border, from Belarus all the way around, well, you’d say that means that he is looking like he’s trying to do something,” the president said. “But then you look at what his past behavior is and what everyone is saying in his team, as well as everyone else, as to what is likely to happen, it all comes down to his decision.”

But Biden again threatened Russia with “enormous consequences” if it invades Ukraine, regardless of whether it would be an all-out invasion or a lesser one. 

“Not only in terms of economic consequences and political consequences, but enormous consequences worldwide,” he said. “This would be … if he were to move in with all those forces, the largest invasion since World War II. It would change the world.”

Ukrainian leaders, meanwhile, have been trying to calm their citizens by insisting a Russian invasion is not imminent. 

Ukrainian President Volodymyr Zelenskyy said late Monday the situation was “under control” and that there is “no reason to panic.” But Ukrainian officials acknowledge the threat is real and were slated to accept a shipment of American military equipment Tuesday to shore up their defenses.

White House press secretary Jen Psaki said Tuesday that Russia is “setting up the predicate for an invasion” through its troop surges at the border, rhetoric and actions such as disinformation campaigns. 

Psaki said the decision to prepare 8,500 troops for possible deployment was made in consultation with NATO allies, adding that some of those troops are stationed in Europe and others are still in the U.S. 

And the State Department's top spokesperson also downplayed recent U.S. actions as supportive, not an escalation.

"Different allies are contributing different elements to this effort to reassure, to reinforce, to deter further Russian aggression," said press secretary Ned Price. "Different allies are contributing in different ways, in a way that is mutually reinforcing."

"Now is not the time for panic. Now is the time for preparation," he added.

In Moscow on Monday, Kremlin spokesman Dmitry Peskov claimed it was NATO and the U.S. who were behind the escalating tensions, not Russia.

“All this is happening not because of what we, Russia, are doing. This is happening because of what NATO, the U.S. are doing,” Peskov told reporters.

Psaki said there’s no truth to that.

“The aggressive behavior here is on the part of the Russians,” she said. “This is a defensive alliance, not an offensive alliance. And what we’re doing here is not making a decision, as has been clear by NATO partners and by the president and members of our national security team, to deploy, but just to be ready.”

Senate Minority Leader Mitch McConnell, R-Ky., on Tuesday commended Biden for his actions toward Russia, saying it appears “the administration is moving in the right direction.”

“What I’ve been hearing since then is encouraging, that they’re prepared to take steps before an incursion, not afterwards,” McConnell said.

Psaki said the Biden administration has held many briefing with congressional leaders about the Russia-Ukraine standoff and welcomed the rare praise from across the aisle.

“I think … standing up for the territorial sovereignty of Ukraine, making clear that one country should not be able to invade and take over territory from another country, that’s not just a Democratic belief or Republican belief, that’s central to who we are as a country,” she said.

The Associated Press contributed to this report.