Sen. Chris Coons (D-Del.) on Thursday said a number of longtime U.S. allies in Europe are worried that Russian President Vladimir Putin could be emboldened and look to “keep going” into other countries if he’s seen as getting a free pass on Ukraine.

Coons, a close ally to former President Biden, said he’d had a number of discussions at a security conference this week in Germany where officials had relayed their fears.

“All of them are alarmed – concerned – that giving Putin a free pass to roll over the rest of Ukraine will send a signal that President Trump no longer respects our commitment to NATO and that Putin will just keep going,” Coons told MSNBC’s Jen Psaki in the interview.

“Once [Putin] reconstitutes his full military, they believe that he will next threaten the Baltic states, Poland, the Czech Republic, that he will threaten all of our core allies in Europe.”

Coons, a member of the Senate Foreign Relations Committee, was among a bipartisan group of lawmakers who attended the recent Munich Security Conference and met with foreign leaders from across Europe while there.

Trump has pushed for an end to the years-long conflict between Russia and Ukraine, and U.S. and Russian officials met in Saudi Arabia on Tuesday to try to hash out an agreement. No representatives from Europe or Ukraine were present.

Trump also has escalated rhetoric against Ukraine and Ukrainian President Volodymyr Zelensky. He called Zelensky “a dictator” and claimed Ukraine started the war, which began with Russia’s invasion of its neighbor.

In a post on Truth Social, Trump warned that Zelensky “better move fast or he is not going to have a Country left.”

Coons said the positioning has raised alarms for the United States’ allies.

“Think about it: On one team you’ve got Russia, China, Iran and North Korea. On the other team you’ve got Ukraine, Germany, Italy, the United Kingdom, France, Belgium, Netherlands – our longtime allies,” Coons said. “Why on earth would it make us safer and stronger for our president to put in with this other team – this team of authoritarians who have undermined and fought against everything we stand for?”

Coons said he also “heard repeatedly” at the conference that Chinese President Xi Jinping is “watching closely” as the U.S. maneuvers an end to the war in Ukraine.

“If we give him the signal that we’re no longer willing to defend Ukraine, his inclination to seize Taiwan will increase dramatically,” he said.