(Bloomberg) -- The U.S. and Germany said any Russian aggression against Ukraine would trigger a serious response from Western allies in the latest effort to deter a conflict in the region. 

U.S. Secretary of State Antony Blinken and German Foreign Minister Annalena Baerbock delivered the warning after a four-way meeting in Berlin with counterparts from France and the U.K., a show of unity amid Russia’s buildup of troops on its border with Ukraine.

“We’re at a decisive juncture,” Blinken said. “We have been very clear throughout if any Russian military forces move across the Ukrainian border and commit new acts of aggression against Ukraine that will be met with a swift, severe, united response from the United States and our partners.”

Blinken offered a show of U.S. support for the country in meetings with the its leaders in Kyiv on Wednesday, as he continues a diplomatic push to head off a Russian invasion that the U.S. has said may be imminent. 

Baerbock indicated Germany would play a role in punishing Russia for military action against its neighbor.  

“Every further Russian aggression would have grave consequences,” she said. “It’s a good and important signal that talks are continuing.”

French Foreign Minister Jean-Yves Le Drian and U.K. Minister of State James Cleverly joined the talks in Berlin earlier Thursday, and Blinken is due to meet with German Chancellor Olaf Scholz later in the day after making a speech at an Atlantik-Bruecke event. He heads to Geneva for talks with his Russian counterpart, Sergei Lavrov, on Friday.

U.S. President Joe Biden said Wednesday he thinks Vladimir Putin -- who denies he plans an invasion -- doesn’t want a full-scale armed conflict with Ukraine but expects Russia to “move in” on its neighbor.

In a news conference marking his first year in office, Biden said that the U.S. and its European allies are united on making sure Russia faces “severe economic consequences.” However, he acknowledged that the NATO alliance is split over what to do if Russia opts for a smaller-scale incursion into Ukraine.

The European Union is steering clear of a group discussion of specific penalties for Russia for the time being, according to people familiar with the matter. Several governments are keen to avoid the debate, fearing it would highlight potential differences within the 27-member bloc.

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