Tom Vanden Brook

USA TODAY

Taliban leader Mullah Akhtar Mansoor was likely killed Saturday in a U.S. drone strike in a remote area of Pakistan, a U.S. defense department official said.

Mansoor, who is believed to be around 48, formally assumed the leadership of the Taliban last year following the death of Mullah Mohammad Omar.

The official, who was not authorized to speak publicly about the attack, said Mansoor was believed killed when the drone hit a vehicle in which he and another militant were riding. The second person was killed by the strike authorized by President Obama, the official said.

Mullah Abdul Rauf, a senior Taliban commander confirmed the death of leader Mullah Akhtar Mansour in U.S. drone strike, the Associated Press reported.

The airstrike by U.S. Special Operations forces occurred along Pakistan's border with Afghanistan, southwest of the town of Ahmad Wal.

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Pentagon press secretary Peter Cook earlier announced the U.S. conducted a strike aimed at Mansoor but said officials were still assessing the result of the attack.

Cook said Mansoor, who had been Mullah Omar's deputy, was "actively involved with planning attacks against facilities in Kabul and across Afghanistan." He said the Taliban leader presented a threat to Afghan civilians and security forces, as well as U.S. and allied forces.

Mansoor was elected head of the Taliban in July but was effectively in charge of the group since the death of the reclusive Mullah Omar as early as 2013, according to the Afghan government. The one-eyed, secretive Mullah Omar hosted Osama bin Laden's al-Qaeda in Afghanistan in the years leading up to the Sept. 11, 2001, attacks.

"We should keep our unity, we must be united, our enemy will be happy in our separation," Mansoor purportedly said in an audio message at the time of his election. "This is a big responsibility for us. This is not the work of one, two or three people. This is all our responsibility to carry on jihad until we establish the Islamic state."

In July, Sirajuddin Haqqani was named the Taliban's new deputy leader. It was not immediately clear who will succeed Mansoor.

Haqqani was the operational head of the militant Haqqani Network that operates in Afghanistan and has been responsible for attacks on foreign and Afghan targets. The State Department named the Haqqani Network a terrorist organization in 2012. The U.S. has a $10 million bounty on Haqqani's head.

The Haqqani Network had worked closely with the Taliban but until the leadership change last year, it had maintained a separate leadership structure.