Afghan First Vice President Marshal Mohammad Qasim Fahim died early Sunday of a heart attack, an official source said. He was 56.

The announcement was made by Aimal Faizi, the spokesman for Afghan President Hamid Karzai, in a statement to the Tolo local television channel.

Faizi called the late vice president the "first voice of President Karzai."

The Afghan president decreed three days of national mourning for Marshal Fahim, whom he described in a communique as a "great patriot and mujahideen, whose death is a great loss for Afghanistan."

In the communique, Karzai expressed "our sincere condolences to his family" and asked Afghans "to pray that God has him in glory."

A former warlord of Tajik ethnicity, Marshal Fahim was defense minister in Karzai's first government after the U.S. invasion that toppled the Taliban regime after the Sept. 11, 2001, terrorist attacks.

After several years away from government, Karzai in 2009 named Marshal Fahim first vice president, a post he occupied until his death.

A member of the Jamiat Islami party, Marshal Fahim was a companion in arms of the famous commander Ahmad Shah Masaoud, who was killed by Al Qaeda shortly before the 2001 terrorist attacks. EFE