Britain must quickly trigger the Article 50 clause that allows talks to start on its exit from the European Union, French Foreign Minister Jean-Marc Ayrault said on Saturday after a meeting of six European foreign ministers in Berlin. It would not be acceptable for Britain to play a "cat and mouse" game, he told reporters.

"Of course a new (British) prime minister must be appointed, that will probably require a few days but this is quite urgent," Ayrault said.

"It's in Britain's interest and in the interest of Europeans not to have a period of uncertainty that would have financial consequences, and that could have economic and political consequences," he added.

Belgium's foreign minister Didier Reynders said Europe must deliver answers on immigration, security and jobs. His Dutch counterpart Bert Koenders said Europe could not accept a political vacuum. "This will not be business as usual," he said.