US troop drawdowns in Afghanistan 'not necessarily' tied to Taliban deal

US Defense Secretary Mark Esper said on Monday that any future troop drawdowns in Afghanistan were "not necessarily" linked to a deal with Taliban insurgents, suggesting some lowering of force levels may happen irrespective of the ongoing peace push.

"I feel confident that we could reduce our numbers in Afghanistan and still ensure that place doesn't become a safe haven for terrorists who could attack the US," Esper said in an interview, without offering a figure.

"And our allies agree we can make reductions as well."

Asked whether such reductions would necessarily be contingent on some sort of agreement with the Taliban insurgency, Esper said, "Not necessarily."

Meanwhile, an Australian man who spent three years in Taliban captivity said on Sunday that he believes US special forces tried to rescue him and an American colleague on half-a-dozen-occasions.

Speaking in Sydney for the first time since he was freed in a prisoner swap deal, 50-year-old Timothy Weeks said he never lost hope, but the captivity "had a profound and unimaginable effect" on him.

Detailing a hellish life spent moving between windowless cells in Afghanistan and Pakistan Weeks said, "After almost 1,200 days, our ordeal ended as abruptly as it had begun."

Weeks and American colleague Kevin King were freed on November 20 as part of a deal between the Taliban, US, Australian and Afghan governments.