Vice President Mohammad Qasim Fahim of Afghanistan, a formidable power broker and former warlord who played a crucial role in ousting the Taliban and shaping the political order that followed, died Sunday, less than a month before Afghans were to elect a new leader.

Fahim, who was said to be either 56 or 57, died of a heart attack, according to a close friend and political ally, Maulavi Ata ul Rahman Salim.

His sudden death created a rift at the center of the Afghan political power structure, removing a crucial player from the factional and ethnic landscape as well as Cabinet politics. Fahim was a foremost leader of the country’s ethnic Tajik minority, and a powerful and early voice in bringing the support of northern warlords to President Hamid Karzai and helping keep peace with Afghan Pashtuns.

Karzai’s office declared three days of national mourning.

Controversial history

On the brink of presidential elections, Afghan and Western leaders had again been looking to Fahim as a potential peacemaker amid a critical leadership transition in wartime.

But his legacy is a controversial one, and his Western backers and other former allies distanced themselves from Fahim in recent years amid continuing accusations of corruption and human rights abuses.

Like many here, Fahim was catapulted to power by the U.S.-led invasion of Afghanistan.

He came to lead the Northern Alliance, a group of militias struggling against the Taliban, just before the terrorist attacks on Sept. 11, 2001, and after assassins for Al-Qaida killed the coalition’s founder, Ahmad Shah Massoud. The alliance’s forces were embattled and outgunned, and Fahim’s position as their leader was hardly secure.

But by the end of that month, the United States turned Fahim into its first proxy in the fight against the militants, and CIA operatives were giving him backpacks stuffed with dollars as American jets bombed the Taliban government’s forces. Within a year, Fahim had parlayed his ties to the United States into a dominant role in the nascent Afghan government and begun building a vast patronage network that would enrich his family and his standing within the Tajik faction. He would also solidify his reputation for violently taking on rivals and critics.

Fahim had not publicly backed any candidate, but he was widely believed to favor the leading opposition candidate, Abdullah Abdullah, a fellow member of the now-defunct Northern Alliance.