KABUL, May 2 (Reuters) -- One of the top candidates expected to bid to unseat Afghan President Hamid Karzai withdrew abruptly from the election race on May 2, dealing a blow to opposition hopes of fielding a contender with a broad enough base to win.
Karzai, who travels next week to meet U.S. President Barack Obama in Washington, confirmed on April 27 that he will stand for another term in an election on August 20.
Candidates have one more week to register, and opponents of the president have met privately to try to field a unified slate.
Gul Agha Sherzai, popular governor of Nangarhar Province in the country's east and a former anti-Soviet guerrilla commander, had been in talks to head up a broad opposition ticket with two vice presidential candidates that would span ethnic lines.
But he told a news conference in the provincial capital Jalalabad that he had met Karzai and been persuaded not to run.
"I visited the president, and hugged his little son and decided to withdraw my candidacy for the presidential elections," the Pakistan-based news agency Afghan Islamic Press quoted him as saying. "I will neither lead this alliance nor announce my candidacy for the presidential election."
Sherzai also said he would resign as governor. But Karzai rejected his resignation and heaped him with praise.
"Hamid Karzai sees Gul Agha Sherzai as a very fine and hardworking governor and a good advisor, and rejects his resignation," the presidential palace said in a statement.
"The president of Afghanistan appreciated Gul Agah Sherzai's announcement he will not run in the presidential election, and called it a positive step toward improving the government and unity of the people of Afghanistan."
Defections appear to have left the opposition in disarray as the election draws closer.
Sherzai is a prominent member of Karzai's own Pashtun ethnic group, Afghanistan's largest, and could have headed an opposition ticket with vice presidential candidates drawn from other groups.
But the opposition has shown little sign of uniting.
Former Vice President Mohammad Qasim Fahim, one of the main leaders of the second largest ethnic group, the Tajiks, withdrew from a major opposition group earlier this month, apparently throwing his support behind Karzai.
Karzai was installed in power under an internationally brokered agreement after U.S.-backed Afghan forces drove Taliban guerrillas from power in 2001. In 2004 he won Afghanistan's first democratic presidential election.
In the years since then, a sharply worsening Taliban insurgency in the south and east, and a state seen as ineffective and corrupt, have damaged his image both at home and among the Western countries supporting his government with troops and cash.
Yet the disarray in the opposition ranks means he will be in a strong position when he flies to Washington next week for his first White House meeting with Obama, along with Pakistan's President Asif Ali Zardari.
The Obama administration, which was initially highly critical of Karzai as ineffective and tolerant of corruption, has since stopped criticizing him in public, and the White House visit will be seen in Afghanistan as a signal of Washington's support.