• Video report by ITV News Washington Correspondent Robert Moore

The countdown to the signing of a peace agreement between the Taliban and the United States to end the 18-year-war in Afghanistan begins Friday night, according to the Associated Press.

The Taliban have promised a seven-day 'reduction of violence' followed by the February 29 signing of a peace agreement with the United States, according to a US State Department official.

The peace deal with pave the way for the withdrawal of US troops from the region and the beginning of talks between the Taliban and Afghanistan's Western-supported government, the official said.

The agreement will be signed in Doha, Qatar, where the Taliban have maintained an office since being toppled from power in Afghanistan in 2001 after they harboured Osama bin Laden and were then invaded by the United States.

Millions of refugees have escaped Afghanistan since the conflict began in 2001. Credit: AP

US Secretary of State Mike Pompeo said the peace agreement will lead to a permanent cease-fire.

It'll include guarantees the Taliban will not use Afghanistan to launch attacks against the US or its allies, and will facilitate the withdrawal of Western troops within 18 months, he said.

There's an estimated 12,000 US troops currently in Afghanistan, and the Pentagon has declined to say whether the US has agreed to cut its troop levels to zero.

There's also currently 1,000 British troops in Afghanistan, mostly involved with training and assisting Afghan government forces. It's not clear whether they will follow the US withdrawal following the deal.

"We are preparing for the signing to take place on February 29,” Pompeo said in a statement issued Friday. “Intra-Afghan negotiations will start soon thereafter, and will build on this fundamental step to deliver a comprehensive and permanent ceasefire and the future political road map for Afghanistan. ‘’

Mike Pompeo said the peace deal will be signed on February 29. Credit: AP

But it's not clear who will be at the table for the intra-Afghan negotiations - the talks most critical to the future peace in the country.

The Taliban have ruled out negotiating with Afghanistan's President Ashraf Ghani, disputing election results that came out this week declaring him the winner.

They said they will talk to government representatives but only as 'ordinary Afghans.'

"(We will) finally lay the groundwork for peace across the country with the withdrawal of all foreign forces," the Taliban said in a statement.

But they added: "the land of Afghanistan (will not) be used against security of others so that our people can live a peaceful and prosperous life under the shade of an Islamic system."

Afghan commandos during their graduation ceremony. Credit: AP

Germany and Norway have both offered to host the intra-Afghan talks but no venue has yet been set. There was also no immediate comment from President Ghani.

The peace deal also calls for the release of 5,000 Taliban prisoners, most of which are being held in jails run by the Afghan government.

There's currently an estimated 2.6 million registered Afghan refugees in the world - the second highest group after Syrians.