New Delhi

Top US generals had warned US President Joe Biden that a rushed withdrawal from Afghanistan could increase risks to Pakistan's nuclear weapons and the country's security, Dawn reported.

"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.

"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, the report said.

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

The Centcom chief also said that the US and Pakistan were involved in ongoing negotiations over the use of a vital air corridor to access Afghanistan, the report said.

"Over the last 20 years we've been able to use what we call the air boulevard to go in over western Pakistan and that's become something that's vital to us, as well as certain landlines of communication," he said.

"And we'll be working with the Pakistanis in the days and weeks ahead to look at what that relationship is going to look like in the future."

Both generals, however, declined to discuss more on their concerns about Pakistan's nuclear weapons and the potential that they could fall into the hands of terrorists.

They said they would discuss this and other sensitive issues in a closed session with the senators.

Secretary Lloyd Austin urged Americans to "consider some uncomfortable truths" before blaming anyone for the fall of Kabul.

"We did not fully comprehend the depth of corruption and poor leadership in their senior ranks, we did not grasp the damaging effect of frequent and unexplained rotations by president Ashraf Ghani of his commanders," he added, the report added.

"We didn't anticipate the snowball effect caused by the deals that Taliban commanders struck with local leaders in the wake of the Doha agreement, and that the Doha agreement itself had a demoralising effect on Afghan soldiers."

The Americans, he said, also failed to understand that Afghan soldiers did not have the motivation to fight for a corrupt government.

"We failed to fully grasp that there was only so much for which - and for whom - many of the Afghan forces would fight," he said.

General Miley noted that the vast majority of Afghan troops "put their weapons down and melted away in a very, very short period of time."

He too blamed the previous Afghan government for failing to inspire the soldiers.