Speaking alongside Gen. Mark Milley, chairman of the Joint Chiefs of Staff, Austin also questioned decisions made over the 20-year course of the US war in Afghanistan.
Thousands who had worked with the US and its allies, as well as up to 200 Americans, remained in the country after the massive airlift ended with the last US soldiers flying out of Kabul.
Nearly 5,500 Americans have been evacuated as part of a mammoth operation that has flown more than 114,000 people from the country since the Taliban takeover.
The participants reiterated that Pakistan was committed to an inclusive political settlement as the way forward, representing all Afghan ethnic groups.
Since the foreign troops started leaving Afghanistan, the Taliban had been extensively fighting with the Afghan government in an attempt to gain control of key areas.