A senior US official on Saturday (local time) said that there was “no fundamental change” after the United States President Joe Biden’s hour-long call with Russian counterpart Vladimir Putin, noting that Moscow may decide to proceed with military action and invasion in Ukraine remains a “distinct possibility.

“US President Joe Biden made clear his stance over the ongoing tension between Ukraine and Russia and said that if Moscow undertook a further invasion of Kiev, Washington along with its allies will respond “decisively” and impose swift and severe costs on the country, according to a White House statement.

In a roughly hour-long phone call between the two leaders, the White House said Biden made clear to Putin what he would be risking with an invasion. In a third conversation amid escalating tensions over Russia’s military buildup at the Ukraine border, Biden underscored Russia’s military buildup on the borders of Ukraine.

“President Biden was clear that, if Russia undertakes a further invasion of Ukraine, the United States together with our Allies and partners will respond decisively and impose swift and severe costs on Russia,” the statement read on Saturday (local time).

The call between the two leaders comes hours after the US moved some of its forces out of Ukraine and ordered the evacuation of most of its embassy staff on Saturday as fears mount that a Russian invasion of the country could take place in the next few days.

Meanwhile, a senior Biden administration official told reporters during a conference call that there was no change by Putin. The official noted that Russia may decide to proceed with military action and invasion remains a “distinct possibility.

“The official described the call as “professional” and noted there was “no fundamental change in the dynamic that has been unfolding now for several weeks.”

“It remains unclear whether Russia is interested in pursuing its goals diplomatically as opposed to through the use of force,” the official said. “We don’t have full visibility into President Putin’s decision-making.”

Secretary of State Antony Blinken held a phone call with Russian Foreign Minister Sergey Lavrov on Saturday, reiterating that a Russian invasion would result in “a resolute, massive, and united Transatlantic response.”

Defense Secretary Lloyd Austin also called his counterpart, Russian Defense Minister Sergey Shoygu, ahead of the Biden-Putin meeting.

In the past 24 hours, multiple other countries — including Israel, Germany, and the U.K. — have been encouraging their citizens to leave and reducing their diplomatic presence.