Christian Democratic Union (CDU) candidate for the party chair Annegret Kramp-Karrenbauer is pictured during a Reuters interview in Berlin, Germany, November 30, 2018. REUTERS/Fabrizio Bensch

BERLIN (Reuters) - The European Union and the United States should consider banning from their ports Russian ships originating from the Sea of Azov after Russia captured three Ukrainian vessels there, a senior ally of Chancellor Angela Merkel told Reuters on Friday.

“One answer might be, for example, to stop Russian ships coming from the region - from the Sea of Azov - from entering European or U.S. ports until this situation with Ukraine is resolved,” said Annegret Kramp-Karrenbauer, who is leading the race to succeed Merkel as leader of the Christian Democrats.

Turning to tensions with the United States, Kramp-Karrenbauer said top executives from German carmakers Volkswagen VOWG_p.DE, BMW and Daimler should be careful not to undermine the EU's trade position when they meet U.S. officials at the White House next week.