President Biden said Wednesday that he believes Russian President Vladimir Putin will advance into Ukraine, but he also tried to address Russia's main complaint, indicating that Ukraine would not join NATO in the near future.

"I'm not so sure he has, he's certain what he's going to do," Biden said. "My guess is he will move in. He has to do something."

Biden, who spoke during a nearly two-hour White House press conference, indicated there was disagreement within NATO about imposing strong sanctions on Russia because it would harm the economies of some European allies.

President Joe Biden addresses reporters questions at press conference in Washington

President Joe Biden answers questions during a news conference in the East Room of the White House on January 19, 2022 in Washington, DC. ( Chip Somodevilla/Getty Images)

Biden vowed that "Russia will be held accountable if it invades" Ukraine and appeared to suggest a "minor incursion" by Russia would call for a different response from the United States.

"It depends on what it does," Biden said, anticipating action from Russia. "It's one thing if it's a minor incursion and then we have to end up having to fight about what to do and not do, etcetera."

PUTIN TO HOLD SUMMIT WITH XI AT START OF OLYMPICS IN BEIJING

But Biden indicated a full-scale invasion would still have severe consequences, saying it would "be a disaster for Russia."

The White House later put out a statement by press secretary Jen Psaki clarifying that any kind Russian military incursion into Ukraine would be met with a "severe" response. She appeared to indicate that a lesser "reciprocal" response would greet more-limited actions, like "cyberattacks and paramilitary tactics."

"President Biden has been clear with the Russian President: If any Russian military forces move across the Ukrainian border, that's a renewed invasion, and it will be met with a swift, severe, and united response from the United States and our Allies," Psaki said. "President Biden also knows from long experience that the Russians have an extensive playbook of aggression short of military action, including cyberattacks and paramilitary tactics. And he affirmed today that those acts of Russian aggression will be met with a decisive, reciprocal, and united response."

Russian President Vladimir Putin toasts during reception for military servicemen who took part in Syrian campaign, at Grand Kremlin Palace on December 28,2017 in Moscow, Russia. (Photo by Mikhail Svetlov/Getty Images)

"If they actually do what they're capable of doing with the forces amassed on the border, it is going to be a disaster for Russia if they further invade Ukraine," he added. "And that our allies and partners are ready to impose severe cost and significant harm on Russia and the Russian economy."

Biden seemed to try to reassure Russia, downplaying the possibility of Ukraine joining NATO "in the near term," saying it is "not very likely"  because more work is needed. 

Putin has described the possibility of Ukraine joining NATO and the alliance deploying weapons there as a "red line" for Moscow. The Kremlin demanded that Washington and its allies make a binding pledge excluding NATO’s expansion to Ukraine, Georgia or any other ex-Soviet nation.

"The only thing I'm confident of is that decision is totally, solely, completely a Putin decision," Biden said of a potential invasion. "Nobody else is gonna make that decision and nobody else is gonna impact that decision. He's making that decision."

CLICK HERE TO GET THE FOX NEWS APP

Last week, Russian diplomats met with officials from the United States and its NATO allies for security negotiations in three European cities amid the massing of Russian troops and equipment near Ukraine's border.

The Associated Press contributed to this article.