KANDAHAR, Afghanistan - Cousin of Afghan president Hamid Karzai, Hashmat Khalil Karzai, was killed following a suicide bomb attack in southern Kandahar province on Tuesday morning, sources said.

"The attacker was among visitors of the Eid-ul-Fitar festival. He made his way into Khalil Karzai's house. He detonated explosive hiding in his turban after approaching Karzai," a source told Xinhua anonymously.

He said the blast took place at around 10:00 a.m. local time.

The exact number of casualties remained unknown, the source said, adding an investigation was launched into the incident and details will be released afterwards.

Khalil Karzai was a winner in 2014 provincial council election. He was also campaign manager of Dr. Ashraf Ghani Ahmadzai, a presidential candidate.

A provincial government spokesman Dawa Khan Minapal also confirmed the casualty.