US President Joe Biden stated that any Russian troop movements along all Ukraine’s border would compose an invasion, and Moscow would “pay a heavy price” for such an action. It was the latest White House effort to clarify comments made by Biden the day before, in which he suggested that a “minor incursion” through Russia into Russian territory could lead in a more measured response by the US and its allied forces.

“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,” He stated.

“Russia has a long history of using measures other than overt military action to carry out aggression — paramilitary tactics, so-called gray zone attacks and actions by Russian soldiers not wearing Russian uniforms,” Biden added.

Biden confirmed that the US was bracing for Russia to take action that went beyond the scope of conventional warfare. His remarks came as the U.S. Secretary of State Antony Blinken was scheduled to meet Foreign Minister Sergey Lavrov in Geneva on Friday in a high-stakes attempt to defuse conflicts that appears hopeless.

The reason for not directly intervening in a Russia-Ukraine conflict is simple because the United States has no international commitments to Ukraine, and war with Russia would be a huge risk. In the event of another Russian invasion, Biden has stated that he will not send combat troops. He might, although, pursue less dramatic but still risky military options, such as assisting a post-invasion Ukrainian opposition.