Afghan President Hamid Karzai has joined thousands of mourners at the funeral of his half-brother, one day after he was assassinated by a longtime member of his own security team.

President Karzai wept openly and kissed the face of Ahmad Wali Karzai during the burial, which was held amid tight security in the family village of Karz in southern Kandahar province on Wednesday.

Officials say the governor of nearby Helmand province escaped injury after his convoy was hit by a roadside bomb while traveling to the funeral.

Ahmad Wali Karzai — a powerful figure in the country's south — was shot dead on Tuesday at his home in Kandahar city by a longtime member of his own security team. The man, identified as Sardar Mohammad, was then killed by other members of the security team.

The Taliban claimed responsibility for the assassination. But Afghan officials said it is not clear whether Wali Karzai's killing was related to the insurgency or to an internal feud.

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

The Obama administration also condemned Wali Karzai's death “in the strongest possible terms.”

Also in Afghanistan, Italian defense officials said on Tuesday that a roadside bomb killed an Italian soldier in western Farah province. Early Wednesday local time, NATO said two of its service members were killed in separate attacks in the south. A NATO statement said one soldier died in a bomb blast, while the other was killed in an insurgent attack.

In other violence, Afghanistan's spy agency said it foiled an attempt by a group of eight terrorists to kill Interior Minister Bismillah Mohammadi during his visit to eastern Paktia province.