Afghan President Hamid Karzai's younger brother – a powerful figure in the country's south – has been assassinated at his home by a trusted bodyguard.

Afghan officials say Ahmad Wali Karzai was shot and killed Tuesday by a senior member of his security detail in Kandahar city. The gunman, who was identified as Sardar Mohammad, was then killed by Wali Karzai's bodyguards.

Officials say Mohammad was a longtime friend of Wali Karzai and both men were from the same village of Karz. Mohammad was said to be meeting privately with Wali Karzai when he shot the president's brother in the head and chest.

The Taliban claimed responsibility for the assassination. But Afghan officials said it was unclear whether Wali Karzai's killing was related to the insurgency or to an internal feud.

In Kabul, Afghan President Hamid Karzai told reporters the killing of his younger brother represents the suffering of all Afghan people. The Afghan leader traveled to Kandahar later in the day for his brother's burial, set for Wednesday.

Ahmad Wali Karzai, the head of the provincial council in southern Kandahar province, was a controversial figure. While he was seen as a key power broker in the region and an ally to international forces fighting the Taliban, Wali Karzai had also been accused of corruption and drug trafficking – allegations he had denied.

The commander of U.S. and NATO forces in Afghanistan, David Petraeus, said Tuesday he condemns the murder of Wali Karzai and that NATO forces will support the Afghan government's efforts to bring justice to those responsible.

The Obama administration also condemned Wali Karzai's death “in the strongest possible terms.” White House spokesman Jay Carney said Tuesday the U.S. will work with Afghan authorities as they investigate the killing.

Wali Karzai survived at least two previous attempts on his life in recent years. In May 2009 insurgents attacked his motorcade, killing one of his bodyguards. Wali Karzai also escaped an earlier attack on his provincial council facilities in Kandahar.

The United Nations said in a recent report that more than half of all assassinations across Afghanistan since March were carried out in

Kandahar city.

Also Tuesday, Italian defense officials say a roadside bomb killed an Italian soldier in the western Afghan province of Farah.