US President Joe Biden on Thursday said that any Russian troop movements across Ukraine's border would constitute an invasion and that Moscow would "pay a heavy price" for such an action.
It was the latest White House effort to clear up comments Biden made a day earlier when he suggested that a "minor incursion" by Russia into Ukrainian territory could result in a more measured response by the United States and allies.
Biden faced an avalanche of criticism from Republicans and Ukrainian officials who said his comments had invited limited military action by Russian President Vladimir Putin.
"I've been absolutely clear with President Putin," Biden said. "He has no misunderstanding: Any, any assembled Russian units move across the Ukrainian border, that is an invasion," said Biden, adding that an invasion would be met with a "severe and coordinated economic response".
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His comments came as US Secretary of State Antony Blinken prepared to meet on Friday in Geneva with Russian Foreign Minister Sergey Lavrov in a high-stakes bid to ease tensions.
Biden said the US was preparing for Russia to take action that fell outside the parameters of a conventional warfare.
On Wednesday, Biden said he thinks Moscow will invade and warned Putin that Russia would pay a "dear price" in lives lost and a possible cutoff from the global banking system if it does.
The US has accused Russia of threatening the foundations of world order with its buildup of an estimated 1,00,000 troops near Ukraine.