It said the Luftwaffe air force had dispatched three planes for the mission early on Wednesday. The planes had first landed in Greece for refuelling.

The aircraft were later expected to fly to Khartoum to evacuate dozens of German diplomats, federal police officers and aid workers.

However, the German military reportedly aborted the mission because of renewed clashes and airstrikes in Khartoum.

Japan and Kenya had also announced they would evacuate their citizens, but the fighting in Sudan has delayed those plans.