President Biden addressed the brewing conflict between Russia and Ukraine during a press briefing Wednesday, saying of Russian President Vladimir Putin, "my guess is he will move in."

Why it matters: U.S. officials have issued a series of warnings about Russia's threatening military buildup on the border with Ukraine, with Secretary of State Antony Blinken saying in Kyiv earlier Wednesday that Russia could invade "on very short notice."

• But as Biden himself acknowledged, it's unclear whether Putin himself has decided what comes next.

Zoom in: "I think he still does not want any full-blown war, number one. Number two, do I think he'll test the west? Test the United States and NATO as significantly as he can? Yes, I think he will," Biden said.

• "But I think he'll pay a serious and dear price for it that he doesn't think now will cost him what it's going to cost him. And I think he'll regret having done it."
• "My guess is he will move in. He has to do something."

Worth noting: Biden said that Russia will be "held accountable if it invades" but added that "it depends on what it does."

• "It's one thing if it's a minor incursion and we end up having to fight about what to do and not do, et cetera."
• But if Russia launches a full-scale invasion of Ukraine, this would be a "disaster for Russia."

Asked later if he was effectively giving Russia permission to make a small incursion, Biden stressed the importance of NATO having a unified response and noted that differences amongst the bloc's members do exist.

• "If it's something significantly short of a significant invasion or not even significant — major military forces coming in...for example, it's one thing to determine that if they continue to use cyber efforts, we can respond the same way, with cyber."
• "There are differences in NATO as to what countries are willing to do, depending on what happens. The degree to which they are able to go."

What they're saying: Rep. Michael McCaul (R-Texas), the ranking Republican member of the Foreign Affairs Committee, called Biden's remarks on Russia's buildup near Ukraine "nothing short of a disaster."

• "He shared the potential disunity of Western nations on tough sanctions and clearly gave Vladimir Putin the green light to launch a 'minor incursion,'" McCaul said in a statement.
• "American credibility with our allies and adversaries alike is hanging in the balance," he added.
• "Rather than promising to act only in the event of a major renewed invasion, what is needed is strong U.S. leadership to rally a punishing response to Vladimir Putin’s aggression right now. I fear this President is not up to the task and he is inviting aggression, not deterring it."

Our thought bubble, from Axios' Zach Basu: Biden's suggestion that there may not be devastating sanctions over a "minor incursion" by Russia is sure to spark alarm in Ukraine, where top officials have been pleading with the U.S. to impose sanctions now to avoid that very scenario.