Taliban leader Mullah Mansour, killed in U.S. drone strike, posed 'imminent' threat, White House says

U.S. forces killed Taliban leader Mullah Akhtar Mansour in an air strike last week because he was engaged in plotting that posed "specific, imminent threats" to U.S. and coalition troops in Afghanistan, the Pentagon said on Monday.

The drone attack against Mansour just inside Pakistan on Saturday was carried out under U.S. rules of engagement that allow U.S. forces to conduct defensive strikes against people engaged in activity threatening U.S. and coalition personnel, said Navy Captain Jeff Davis, a Pentagon spokesman.

President Barack Obama approved the strike on Mansour based on a law authorizing military force in Afghanistan following the Sept. 11 attacks, Pentagon officials said.

• Taliban leader Mullah Mansour killed in U.S. drone strike

Since the strike was conducted in Pakistan, it required presidential authorization. Davis told reporters it was the first time he was aware of that the U.S. military had conducted an attack inside Pakistan under the Pentagon's rules of engagement governing defensive strikes.

Other strikes inside Pakistan, including one that killed al -Qaeda leader Osama bin Laden in 2011, have been based on rules authorizing counterterrorism operations, a Pentagon official said.

"This was considered a defensive strike and given the location [Pakistan]required a higher level of approval," Davis told a briefing. Pakistan has called the strike a violation of its sovereignty.

"This [Mansour]was an individual who was specifically targeting U.S. and coalition personnel and had specifically engaged in operations in the past that resulted in U.S. and coalition personnel being killed," Davis said.

Pressed on whether Mansour had simply been engaged in general plotting or if there was something more specific in the works, Davis said the Taliban chief had been plotting "specific actions, specific things ... in real time."

Asked if the threats were imminent, he said: "Yes, specific imminent threats to U.S. and coalition personnel ... in Afghanistan."

Taliban meets to replace Mansour

Senior Afghan Talibanfigures were meeting on Monday to agree on a successorMansour.

The Taliban have so far made no official statement on thefate of Mansour, who assumed the leadership only last year.But senior members have confirmed that their main shura, orleadership council, has been meeting to discuss the successionin a bid to prevent factional splits from fragmenting themovement.

Obama, on a three-day visit to Vietnam, reiterated supportfor the Western-backed government in Kabul and Afghan securityforces, and called on the Taliban to join stalled peace talks.

Obama calls for peace talks

Calling the death "an important milestone", Obama saidMansour had rejected peace talks and had "continued to plotagainst and unleash attacks on American and coalition forces."

"The Taliban should seize the opportunity to pursue the onlyreal path for ending this long conflict joining the Afghangovernment in a reconciliation process that leads to lastingpeace and stability," he said.

However, he stressed that the operation against Mansour didnot represent a shift in U.S. strategy in Afghanistan or areturn to active engagement in fighting, following the end ofthe international coalition's main combat mission in 2014.

The U.S. currently has 9,800 troops in Afghanistan, dividedbetween a NATO-led mission to train and advise local forces anda separate counterterrorism mission fighting militant groupssuch as theIslamic State of Iraq and Syria (ISIS)and al-Qaeda.

A decision is expected later this year on whether to stickwith a timetable that would see the number of troops cut to5,500 by the start of 2017.

Can Taliban unite?

The Taliban, which have previously rejected ouvertures tojoin talks with President Ashraf Ghani's government, have beenpushing Afghan security forces hard since the launch of theirspring offensive in April, but the attack on Mansour is likelyto disrupt operations, at least temporarily.

Serious divisions emerged last year when it was confirmedthat Mullah Mohammad Omar, the group's founder, had been deadfor two years, leaving his deputy Mansour in effective charge ofthe movement and open to accusations he deceived his commanders.

One senior member of the shura, which is based in thewestern Pakistani city of Quetta, told The Associated Pressthat the choice for thenext leader appeared to be shaping around Mansour's deputy,Sirajuddin Haqqani, or a member of the family of Mullah Omar,such as his son, Mullah Mohammad Yaqoob.

Haqqani, leader of an affiliated network blamed for a seriesof high-profile suicide attacks in Kabul, had the backing ofPakistan, while Yaqoob had support among members of the AfghanTaliban, the shura member said.

"We prefer someone from Omar's family to put an end to allinternal problems," he said.