NATO secretary general Jens Stoltenberg called on the Taliban on Tuesday to facilitate the departure of all those who want to leave Afghanistan, and said the Western defence alliance has agreed to send additional evacuation planes to Kabul.

Germany’s chancellor Angela Merkel has warned that Afghans fleeing to neighbouring countries could make their way to Europe, in a repeat of the 2015 migrant crisis, if they do not receive sufficient humanitarian assistance.

Ms Merkel wants refugees firstly guaranteed safety in countries neighbouring Afghanistan, with the European Union to later consider if it can take people in.

“Reaching a common position within the EU is not easy. It is a weakness of the EU that we have not created a common asylum policy,” she told a news conference.

Germany opened its borders six years ago to more than one million migrants, many of them Syrians, fleeing war and poverty: a move that won Merkel plaudits abroad but which eroded her political capital at home. She plans to stand down after a September 26 federal election.

Armin Laschet, the Christian Democratic Union (CDU) chairman running to succeed her as chancellor, called for future military interventions abroad to have a clear goal, timeline and exit strategy.

“The lesson of the last 20 years is that the goal of regime change, to intervene militarily to end a dictatorship in order to build a democracy, has almost universally failed,” he said in Rostock in northern Germany.