"We are deeply concerned about the safety of our colleague," Daniel O'Malley, ICRC's deputy head of delegation for Somalia, said in a statement.

"We call for her immediate and unconditional release," O'Malley added.

The abduction took place on Wednesday night when armed men entered the ICRC compound in Mogadishu.

"The ICRC is in contact with various authorities to try and secure her release. It is not appropriate to provide any additional information at this stage," the aid group said.

Abdi Asiis Hildhibn, the spokesman for the internal security minister, told media that gunmen stormed ICRC headquarters in Mogadishu and kidnapped a German nurse.

"We know the leader of the gunmen who abducted the aid worker, we are investigating the issue."