The outgoing U.S. defense secretary is in Afghanistan on a previously unannounced farewell visit.

Robert Gates arrived in Kabul Saturday where he is expected to meet with senior Afghan officials, as well as visit the U.S. troops.

Earlier in the day at a security conference in Singapore, Gates said there could be peace talks with the Taliban within a year.

He said the talks would be a result of NATO's ground advances in Afghanistan that have put pressure on the insurgents.

The defense secretary said if the international coalition can sustain its successes, then the possibility of political talks and reconciliation might be “substantive enough” to offer some “hope of progress.”

However, Secretary Gates stressed the Taliban will have to cut ties with al-Qaida and surrender all arms if the Taliban is to have any role in the future of Afghanistan.

The U.S. has set next month as the start date for withdrawing troops from Afghanistan. U.S. and NATO forces are scheduled to transfer security responsibilities to Afghan forces by the end of 2014.

It has been nearly 10 years since U.S.-led forces invaded Afghanistan to topple the Taliban government, which sheltered al-Qaida leader Osama bin Laden.

Bin Laden, who orchestrated the September 11, 2001 terrorist attacks in the U.S., was killed last month by U.S. commandos who raided his hideout in Pakistan.