President Joe Biden said he had warned his Russian counterpart Vladimir Putin of unprecedented US sanctions if Russia attacks Ukraine.

“I made it very clear, if in fact, he invades Ukraine, there will be severe consequences, severe consequences — economic consequences like none he’s ever seen or ever have been seen,” Biden told reporters at the White House.

Biden said that in addition to economic measures, a new Russian attack on Ukraine would trigger a bolstered US military presence on the territory of NATO allies in eastern Europe.

“We would probably be required to reinforce our presence in NATO countries to reassure particularly those in the eastern flank. In addition to that, I made it clear that we would provide a defensive capability to the Ukrainians as well,” he said.

However, Biden said that sending US troops to defend Ukraine from Russia is “not on the cards,” because the country is not part of NATO.

Biden said he was sure Putin understood the US position after their talks.