Ahmed Wali Karzai was shot and killed, according to a provincial spokesman

President Hamid Karzai’s powerful and controversial half brother, Ahmed Wali Karzai, was shot and killed Tuesday by a senior member of his police security detail — an assassination that could set off a chaotic power struggle in a province considered key to Western military efforts.

Ahmed Wali Karzai was the undisputed kingmaker of Kandahar province, the ancestral home of the Karzai clan, and word of his death sent shock waves through the province and Afghanistan’s wider political world.

A solemn Hamid Karzai confirmed his half brother’s death, describing him as having been “martyred” in his home. Pale but composed, the Afghan leader appeared at a news conference with visiting French President Nicolas Sarkozy less than three hours after the killing.

“Every family in Afghanistan has suffered such pain,” he said, speaking in measured tones. “I hope the miseries of our people end one day, and peace and stability reign in our country.”

A provincial spokesman, Zalmay Ayoubi, initially described the assailant as a bodyguard, but later said he was a company commander in the Afghan national police who was a senior member of Karzai’s security detail. The man, identified as Mohammed Sardar, had a long association with the family and had previously worked as a bodyguard for another Karzai brother.

A provincial government official speaking on condition of anonymity said the shooting occurred as Karzai was receiving guests at his heavily guarded compound. Every day, dozens of supplicants turned up to ask him for help or favors, and turbaned tribal elders would routinely come to discuss business or ask for help in mediating disputes. American military officials often visited the compound as well.

Karzai had left a meeting to go into an adjacent room with Sardar when gunfire was heard, the official said. The assailant in turn was shot dead almost immediately by other members of Karzai’s security detail. Karzai was rushed by aides to a nearby hospital, but could not be revived.

The Taliban claimed responsibility for the killing. But the group often makes opportunistic claims of being behind attacks against the government or NATO forces, and it could not immediately be determined whether the assailant had acted at the group’s behest or had some other motive. Karzai had many personal and political enemies stemming from clan rivalries and the sometimes cutthroat business dealings in which he was involved.

Taliban spokesman Qari Yousaf Ahmadi, in a statement, referred to the killer by name and suggested he had been a sleeper agent for some time. The attack, he said, was aimed at Hamid Karzai’s “puppet regime.”

Ahmed Wali Karzai was the head of Kandahar’s provincial council, but he wielded far more power than his official position would dictate. Critics, including U.S. officials, said he was deeply involved in corruption, some of it stemming from Kandahar’s flourishing drug trade.

In secret diplomatic documents that were disclosed last year by Wikileaks, American diplomats portrayed Karzai — inevitably referred to as “AWK” — as a Mafia-like figure, entangled in a variety of illegal activities. Karzai consistently denied the allegations, and also hotly disputed reports of his involvement with the CIA.

Bearded and thick-lipped, the younger Karzai bore some resemblance to his elder half brother. Like him, he could present a charming and urbane demeanor, speaking nearly unaccented American-style English. But like his famous brother, he also had a temper, and those around him feared his wrath.

American officials for a time had pressed for Karzai’s removal from his post, but the Afghan president staunchly defended him, and in the end U.S. officials decided that without his assistance, it would be difficult to move ahead with their anti-Taliban campaign in Kandahar. A U.S.-led offensive last summer drove insurgents from longtime strongholds around Kandahar city.

Efforts to follow that military push with better governance have proved more problematic, in part due to pervasive corruption and inefficiency. A U.S. civilian official in Afghanistan’s south, speaking on condition of anonymity because he was not authorized to discuss the assassination, said Karzai’s death would undoubtedly complicate Western efforts in the south, the Taliban heartland.

Official American condolences were carefully worded, condemning the killing and offering sympathies to the Afghan president for his loss while avoiding commentary about the dead man himself. U.S. Gen. David H. Petraeus, the outgoing commander of Western troops in Afghanistan, said the NATO force would do all it could to help Afghan authorities bring those involved to justice.

In the dusty streets and bazaars of Kandahar, the word of Karzai’s death spread like wildfire. He was a much-feared figure, and some expressed relief over his death, saying he wielded life-and-death power over too many people. Others expressed apprehension over the struggle for spoils that seemed certain to follow his disappearance from the scene.

“He was a bad character,” said a Kandahar shopkeeper named Assadullah, who uses only one name. “He was more powerful than the police, the governor, than anyone.”

Assassinations are commonplace in Kandahar, and are sometimes carried out by trusted associates of the targeted person, or by someone in uniform who can circumvent the extremely heavy security that surrounds all prominent figures. In April, Kandahar’s provincial police chief was killed by an assailant who managed to talk his way into the fortified police headquarters, saying he had an important message for the chief.

The Karzai compound, located in the center of Kandahar, was one of the city’s most heavily secured complexes, with high concrete barriers and several layers of guards and checkpoints. Most vehicles could not enter, and guests routinely underwent body searches.

Karzai had survived several previous assassination attempts, but said in an interview with the Los Angeles Times in 2009 that he did not dwell on his personal safety. “I never think about it,” he said. “It’s not something I can worry over.”

laura.king@latimes.com

Special correspondent Aimal Yaqoubi in Kabul and a special correspondent in Kandahar contributed to this report.