Afghan President Hamid Karzai's half-brother, a lightning rod for criticism of all that is wrong with the Afghan government, was assassinated at his home in southern Afghanistan today, an official said.

The death of Ahmed Wali Karzai was confirmed by Zalmai Ayubi, the spokesman for Kandahar province, and Sediq Sediqqi, a spokesman for the Ministry of Interior.

The Taliban claimed responsibility, saying it was one of their greatest achievements.

Ahmed Wali Karzai, who was head of the Kandahar provincial council, had become a political liability for the Karzai government. But the president repeatedly defended him, denouncing accusations that his brother was involved in criminal activities in the restive south.

Ahmed Wali Karzai has been the reported target of multiple assassination attempts.

In May 2009, his motorcade was ambushed by insurgents firing rockets and machine guns in eastern Nangarhar province. One of his bodyguards was killed, but he was not harmed.

That attack came less than two months after four Taliban suicide bombers stormed Kandahar's provincial council office, killing 13 people in an assault that Ahmed Wali Karzai said was aimed at him.

A member of Ahmed Wali Karzai's private security team killed him with an AK-47, according to a person who witnessed the killing.

Rangina Hamidi, a resident of Kandahar and daughter of the city's mayor, said he is survived by five children - two sons and three daughters. She said his youngest son was born about a month ago.

"It is his one-month-old child who is never going to see his father that I cry about," she said sobbing on the phone. "How many orphans and widows are we creating in this country?"