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."