US Vice President JD Vance has called on Europe to do more to curb illegal migration, calling it the continent's "most urgent" challenge.

Vance was speaking at the Munich Security Conference, a day after an Afghan man was arrested in the southern German city over a car-ramming attack that injured 36 people.

"How many times must we suffer these appalling setbacks before we change course and take our shared civilization in a new direction?" Vance said, adding that the European electorate did not vote to open the "floodgates to millions of unvetted immigrants."

He also urged countries in Europe to take responsibility for their own defense so that Washington could focus on threats elsewhere.

"We think it's an important part of being in a shared alliance together that the Europeans step up while America focuses on areas of the world that are in great danger," Vance said.