Taliban leader Mullah Akhtar Mansoor's death a serious blow to Pakistani-based Taliban

Afghanistan's Taliban leader Mullah Akhtar Mansoor was believed to have been killed in a U.S. airstrike in Pakistan on Saturday, May 21.

Mansoor's death, which was quickly confirmed by Afghan officials the following day, could deal a serious blow to the Pakistani-based Taliban militant group and enrage the Pakistani government.

"There has been an increase in the Taliban's casualties," former Afghan ambassador to France and Canada Omad Samad told Al Jazeera. "This particular news, if confirmed, is going to be a double blow to the Taliban - not only from a political leadership point of view, but I also think it will be translated on the battlefield."

While the U.S. Department of Defense stated that Saturday's precision airstrike targeted the Taliban leader, U.S. officials have yet to confirm Mansoor's death. U.S. Secretary of State John Kerry said during a news conference in Myanmar on Sunday that both leaders of Afghanistan and Pakistan had been notified of the airstrike.

However, Pakistan's Ministry of Foreign Affairs issued a statement denouncing the airstrike as "a violation of [the state's] sovereignty" and claiming that the country was notified of the attack only after it already happened.

Mansoor's death is believed to enrage the Pakistani government that helped secure Mansoor's leadership in the insurgent group following Mullah Omar's death. Pakistan has maintained its position to exhaust peace talks with the Taliban, but Pentagon spokesman Peter Cook asserted that Mansoor was an obstacle for peace between the Afghanistan government and the Taliban, as reported by The Guardian.

The Afghan government had also previously warned that the Quadrilateral Coordination Group (QCG) would take action for the Taliban's refusal to participate in the peace talks, according to Al Jazeera's Mohammad Vall.

Afghanistan's National Directorate of Security was the first to confirm Mansoor's death in southwestern Baluchistan province. Afghan Chief Executive Abdullah Abdullah also took to Twitter to announce that the Taliban leader was killed at 4:30 p.m. Saturday when Mansoor's car was attacked by a U.S. drone strike.

According to AlJazeera, Pakistani security officials informed AFP news agency that two bodies were found in the car destroyed along the border with Afghanistan. The first body was identified by his relatives as the driver Muhammad Azam while the second body, suspected to be Mansoor, carried a Pakistani passport and a valid Iranian visa with the name of Muhammad Wali.