Pakistan denies any links to the spate of recent attacks in the Afghan capital and maintains no Taliban sanctuaries are present on its side of the border.
The Taliban confirmed Monday that its deputy chief was among several militants killied in a recent USA drone strike near Pakistan's volatile border with Afghanistan.
Taliban militants are yet to make comments on the situation.
Mehsud was killed in a drone strike in North Waziristan, located near the border with Afghanistan, the group said in a statement, the BBC reported.
Sajna was believed to be residing in Khost and was returning to the Waziristan region with his fighters when the drone hit them, according to sources within his Mehsud tribe.
Pakistani intelligence officials say a US drone strike has hit a militant compound in a northwestern tribal region near the Afghan border, killing seven militants from the Taliban-affiliated Haqqani network.
Sajna was wanted in America for his role in terrorist attacks against USA citizens.
U.S. President Donald Trump in August unveiled his new strategy for the South Asia region, under which Washington has deployed 3,000 more troops to Afghanistan to train, advise, and assist local security forces, and to carry out counterterrorism missions. A feared militant commander, he also claimed to have masterminded the 2012 jailbreak in the northwestern town of Bannu that resulted in the escape of almost 400 inmates, including several high-profile militants.
The assistance will support the government of Pakistan's efforts to provide improved access to and quality services for its citizens, implement political and economic reforms, and foster a more inclusive and tolerant environment, says the State Department.