Biden attempts to clarify 'minor incursion' comment, says any Russia troops into Ukraine 'invasion'

President Biden on Thursday attempted to clarify remarks a day earlier in which he suggested Russia might launch a "minor incursion" into Ukraine, not a full-scale invasion.

"I've been absolutely clear with [Russia] President Putin. He has no misunderstanding. If any assembled Russian units move across the Ukrainian border, that is an invasion," Biden said at an event on infrastructure, according to The Hill newspaper.

The "incursion" comment Wednesday sparking national and international concern including Ukraine Foreign Minister Dmytro Kuleba saying such a distinction could create a window of opportunity for Putin to invade, while also saying he still believes his country has U.S. support.

"Let there be no doubt at all that if Putin makes this choice, Russia will pay a heavy price," Biden also said Thursday. "The Ukrainian foreign minister said this morning that he's confident of our support and resolve and he has a right to be." 

Putin is angry over neighboring Ukraine's efforts to join the North Atlantic Treaty Organization, or NATO, and has stacked troops along the Russia-Ukraine border in an apparent act of international brinksmanship. 

Biden said Wednesday in a White House address: "I think what you’re going to see is that Russia will be held accountable if it invades, and 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 to do."

He attempted in the ensuing press conference to clarify that he was suggesting any response would require unity among NATO allies, The Hill also reports.

White House press secretary Jen Psaki told Fox News on Thursday morning: "The president has conveyed directly to President Putin that if there is a movement of any military troops across the border, that is an invasion. If they go in, that is an invasion and there will be severe economic consequences."

She released a statement Wednesday night with similar wording.