Afghan officials disqualified more than half of the candidates who registered for the 2014 presidential election, marking a chaotic opening stage in the country's first democratic transfer of power. (NOORULLAH SHIRZADA/AFP/Getty Images)

More than half of Afghanistan’s presidential candidates were disqualified by the country’s electoral body Tuesday, although major power players and regional strongmen, including a brother of President Hamid Karzai, remain on the list for the April vote.

Ahmad Yusuf Nuristani, the head of the Independent Election Commission (IEC), said dual citizenship and lack of enough voters’ signatures were among the reasons the IEC removed 16 candidates from the list.

Each candidate had been required to collect 100,000 signatures from would-be voters representing all of the country’s 34 provinces.

A successful election is viewed as a key test of Afghanistan’s progress since the Taliban’s ouster in late 2001 by U.S.-backed forces. The vote will be held as U.S. and NATO forces ramp up their withdrawal from the country, which is grappling with a resurgence by the militant organization.

Western donors, which have provided most of the funding for development and other aid needs for more than a decade, have linked continuation of their largess to the formation of a credible government based on the outcome of the April vote.

Karzai, who has led Afghanistan since the Taliban’s ouster, cannot run for a third term, and an uneventful transition between him and a duly elected successor would mark the first peaceful handover of power through a democratic process in Afghanistan’s history.

Among those removed from the list Tuesday was the sole female candidate, a woman from an area with a heavy Taliban presence. The disqualified candidates, as well as one removed earlier, can appeal the IEC decision to the Election Complaints Commission within 20 days, Nuristani said. A final list will be issued in several weeks.

Most of the 10 approved by the IEC are viewed as pro-Karzai figures, with former foreign minister Zalmai Rassoul and the president’s elder brother Qayum Karzai among those said to be his favorites.

Others approved include Abdullah Abdullah, who also served as a foreign minister under Karzai and ran against him in a 2009 election; Karzai adviser and former finance minister Ashraf Ghani; and Abdurrab Rasul Sayyaf, a conservative Islamist who has been accused of human rights abuses.

Some other factional leaders, many of whom played key roles in the Taliban’s removal from power but are widely considered perpetrators of grave abuses, are among the qualifying candidates’ running mates.