U.S. Vice President JD Vance accused European leaders on Friday of censoring free speech and failing to control immigration, drawing a sharp rebuke from Germany's defence minister and overshadowing discussions on the war in Ukraine.

The prospect of peace talks had been expected to dominate the annual Munich Security Conference after a call between U.S. President Donald Trump and Russian leader Vladimir Putin this week but Vance barely mentioned Russia or Ukraine in his speech to the gathering.

He said the threat to Europe that worried him most was not Russia or China but what he called a retreat from fundamental values of protecting free speech - as well as immigration, which he said was "out of control" in Europe.

German Defence Minister Boris Pistorius hit back in his speech to the conference later in the day, calling Vance's remarks "unacceptable".

He said Vance had called into question democracy not only in Germany but in Europe as a whole.