The Chief of Army Staff of Pakistan Army, (reporting name: COAS), is the four-star rank appointment in the Pakistan Army, held by the senior four-star rank officer appointed by the President of Pakistan, on a summary sent by Prime Minister of Pakistan . The Chief of Army Staff post has historically been vested with proportionately more powers because of the recurrent military takeovers in the country. It is the highest and most prestigious four-star assignment, unless the four-star officer is appointed as the Chairman of the Joint Chiefs of Staff Committee of the Pakistan Armed Forces. The appointment is in principal for three years subject to extensions granted by The President of Pakistan on recommendation from The Prime Minister of Pakistan. The appointment is vested with complete operational, training and logistics commands unlike the pattern followed in Western Commands where the Chief of Army Staff is the training and logistics chief while operational command rests with the Ministry of Defense. The current Chief of Army Staff is General Ashfaq Parvez Kayani. The COAS operates from Army Combatant General Headquarters (GHQ) in Rawalpindi, the twin city of the capital Islamabad. Under the Constitution of 1973 presently in vogue, the Chief of Army Staff is subordinate to the Defense Minister of Pakistan, Secretary General/Secretary Defense and reports directly to the civilian leadership.