European Commission President Ursula von der Leyen said forcing Ukraine into a bad deal to bring the war with Russia to an end would harm US interests.

"A failed Ukraine would weaken Europe, but it would also weaken the United States," von der Leyen said.

She made the comments at the Munich Security Conference, which is being overshadowed by uncertainty about US policy on Ukraine. On Thursday, US President Donald Trump surprised many in Europe when he held a phone call with his Russian counterpart about ending the conflict without first consulting European leaders or Ukraine.

Von der Leyen urged Trump to work together for a "just peace."

She also said the European Union needed to drastically increase its defense spending and suggested relaxing the bloc's strict debt rules as one way to make such a surge possible.

"This will allow member states to substantially increase their defense expenditure," the EU chief said.

EU members are obliged to keep their deficit below 3% and their debt ratio below 60% of GDP.