Taliban

Afghanistan's main intelligence agency announced Mullah Omar's death earlier Wednesday and said he'd been dead for more than two years.

White House spokesman Eric Schultz isn't commenting on the time frame, but he says the U.S. intelligence community is looking into the circumstances around Mullah Omar's death.

Abdul Hassib Seddiqi, the spokesman for Afghanistan's National Directorate of Security, said Wednesday that Mullah Omar died in a hospital in the Pakistani city of Karachi in April 2013.

"We confirm officially that he is dead," he told The Associated Press.

The confirmation comes two days before the Afghan government and the Taliban are to hold their second round of official peace talks in Pakistan.

The brazen attack on the symbolic centre of power raises questions about the NATO-trained Afghan security forces' ability to cope with militant attacks.

The attack began when a Taliban fighter driving a car loaded with explosives blew up outside the parliament's gates, Kabul police spokesman Ebadullah Karimi said.

Six gunmen who took up positions in a building near parliament were killed after a gun battle lasting nearly two hours, Mr Karimi said.