“We estimated an accelerated withdrawal would increase risks of regional instability, the security of Pakistan and its nuclear arsenals,” Chairman of the Joint Chief General Mark Milley told the Senate Armed Services Committee on Tuesday as quoted by Dawn News.

“We need to fully examine the role of Pakistan sanctuary,” the general said, while emphasising the need to probe how the Taliban withstood US military pressure for 20 years.

General Milley and General Frank McKenzie, the leader of US Central Command, also warned that the Taliban Pakistan will now have to deal with would be different from the one they dealt with earlier, and this would complicate their relations, reports Dawn News.

“I believe Pakistan's relationship with the Taliban is going to become significantly more complicated as a result of the US withdrawal from Afghanistan,” General McKenzie told the lawmakers.

Afghanistan is currently controlled by Taliban insurgents who captured the country after entering Kabul city on Aug 15.

Taliban's victory is also fuelled by active Pakistan military and diplomatic support to the insurgent group.