Afghan Defence Minister Abdul Rahim Wardak resigned on Tuesday after losing a no-confidence vote in parliament on his handling of security and being relegated to an acting role as President Hamid Karzai searched for a replacement.Wardak, in charge of the army and one of the country’s two key security ministers, told reporters he respected parliament’s decision, which could complicate NATO plans to hand security responsibilities to Afghan forces before the end of 2014."I respected the parliament’s decision to twice appoint me as defence minister, and now I accept the parliament decision to remove me. I resign my position,” Wardak told journalists.The fractious parliament voted on Saturday to remove Wardak and Interior Minister Bismillah Mohammadi after recent insurgent assassinations of senior officials, as well as cross-border attacks blamed on Pakistan.Wardak’s decision leaves the vital position of defence minister vacant at the peak of the summer fighting months and as U.S. and French troops draw down numbers and hand over to Afghan forces.It was not immediately clear how soon Karzai would be able to replace the veteran four-star general and ethnic Pashtun from eastern Wardak province, who is credited by Western diplomats with helping forge the fledgling Afghan National Army into an increasingly effective force against insurgents.Violence in Afghanistan is at its fiercest since U.S.-led Afghan troops overthrew the Taliban government in 2001. Insurgents have extended their reach from traditional strongholds in southern and eastern areas to parts of the country once considered relatively safe.Insurgents on Tuesday detonated a remote-control bomb under a mini-bus on Kabul’s outskirts, killing nine civilians, while a truck bomb also exploded outside a NATO base south of the city, wounding 11 people, including several foreign soldiers.Agencies