Rocket-propelled grenades and machine gunfire rained down on a motorcade carrying the brother of Afghanistan's president in an apparent assassination attempt, the brother said. A bodyguard was killed.

Ahmad Wali Karzai said his convoy was on the way back to Kabul from eastern Nangarhar province when gunmen attacked them in Surobi, a mountainous area about 25 miles from the capital. The younger brother of President Hamid Karzai was not harmed.

Wali Karzai was returning from a trip to the eastern city of Jalalabad, where he went Sunday to thank Nangarhar Gov. Gul Agha Sherzai for not running against his brother in this summer's presidential election.

Gunmen fired on the cars after they entered the Surobi pass, said Abdul Jalal Shamal, the Surobi district police chief.

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"All of the sudden, we heard shooting," Wali Karzai said, speaking in English. Two police officers were thrown from the pickup truck behind his vehicle, he said, adding that he only realized one of his bodyguards had been shot when they went back to collect the officers, who were unharmed. They rushed the bodyguard to a hospital, but he died while being treated.

Wali Karzai, who is the president of the provincial council of the southern Kandahar province, did not comment on who might want to kill him.

Kandahar province is the spiritual birthplace of the Taliban, the hard-line Islamist militiamen who ruled Afghanistan from 1996 to 2001 and are now waging an insurgency against President Karzai's government. The president has escaped several assassination attempts himself since he took power after the fall of the Taliban regime.

Southern Afghanistan also sits at the heart of the booming heroin business, and local and international media reports have alleged that Wali Karzai is involved in the opium poppy trade.

No one has ever proven he is involved, and Wali Karzai has repeatedly denied the charge, saying Western powers use the issue to pressure the president and deflect attention from their own failures.

The younger Karzai said he was certain that he was the target of Monday's attack because many people knew he had visited Sherzai and because the gunmen only fired on the front of the convoy. Members of parliament and other government officials who were part of the delegation were riding farther back in the convoy, he said.

"They didn't target anyone else," Wali Karzai said. The convoy continued on to Kabul after the incident.

The attack comes less than two months after four Taliban suicide bombers stormed Kandahar's provincial council office, killing 13 people in an assault that Wali Karzai also said was aimed at him. A Taliban spokesman said the attack targeted the general compound. The president's brother had left the building a few minutes before that attack.

Wali Karzai said Sherzai's decision to bow out of the presidential race would prevent potential tribal clashes in the southern region where both Sherzai and the president hail from.

Sherzai had been seen as one of the few serious rivals to Karzai's re-election hopes.

Also on Monday, a group of Afghan army soldiers in Jalalabad opened fire in a market, killing three shopkeepers, police said.

The troops were being held in an army compound, said provincial Police Chief Gen. Mohammad Ayub Salangi. A police spokesman had previously said four were arrested.

Salangi did not provide further details, saying they are still investigating.

The incident sparked a protest in the street of the city, with hundreds of residents shouting "Death to the Afghan Army!" as they marched.

Civilian casualties have become an increasingly contentious issue in Afghanistan with a surge in deaths over the past year. A record 2,118 civilians died from violence last year according to the U.N., up from 1,523 the previous year.

More than half of those deaths were inflicted by insurgents, but enough have been attributed to the military that Afghans are increasingly calling for better safeguards.