The Afghan government and the Taliban will this weekend begin talks to end nearly two decades of war, though few expect a peace deal any time soon. The two sides will meet in the Qatari capital Doha from Saturday, six months later than planned owing to bitter disagreements over a controversial prisoner swap.

Secretary of State Mike Pompeo will travel to Doha for the opening of the US-backed negotiations, as President Donald Trump seeks to honour his pledge to halt the country's "endless wars" overseas with just two months to go until he faces re-election.

The talks had originally been slated to start in March but were repeatedly pushed back amid disputes over a prisoner exchange that included the release of hundreds of battle-hardened Taliban fighters.

Trump announced Pompeo would depart Thursday "on a historic trip to Doha, Qatar, for the beginning of intra-Afghan peace negotiations."

The insurgents, the Afghan government and Qatari officials all confirmed on Thursday the talks would begin Saturday following an opening ceremony in Doha.

Pompeo, in a statement, called the talks a "historic" opportunity to end decades of war and bloodshed, adding "This opportunity must not be squandered". 

Qatar's foreign ministry said the talks "are a serious and important step towards establishing sustainable peace in Afghanistan".

Afghanistan's former chief executive Abdullah Abdullah, who now heads the High Council for National Reconciliation (HCNR), was set to fly to Qatar on Friday. "HCNR hopes that after a long wait, talks will lead to permanent peace & stability & an end to war," the council said on Twitter.

The talks come as Trump faces uncertain prospects in the November 3 election and he has pushed hard to pull back US forces from Afghanistan, where they rose to more than 12,000 under his watch to pressure the Taliban and Islamic State.

The number fell to about 8,600 in July following a February accord between Washington and the Taliban, and is expected to be around 4,500 in October.

- Freed insurgents -

Trump believes pushing ahead could boost his standing among voters fed up with conflicts that began almost two decades ago, after the September 11, 2001 Al Qaeda attacks.

The announcement of the start of peace talks was delivered just hours after a final hurdle -- the fate of six Taliban prisoners linked to the killings of French and Australian civilians and troops -- appeared to have been resolved.

Peace talks were delayed for six months as the Taliban and Kabul conducted a US-brokered prisoner exchange. The Taliban released 1,000 Afghan troops, while Kabul freed 5,000 insurgents. 

Paris and Canberra had objected to the freeing of six militants tied to killing French and Australian nationals, but a compromise appeared to have been struck by sending the insurgents into custody in Qatar.

Late on Thursday, the Taliban confirmed the six prisoners had arrived in Doha. They had been flown out of Kabul on a special plane, a Taliban source in Pakistan had told AFP earlier on Thursday. 

The six included a former Afghan soldier charged with the killing of five French soldiers and injuring 13 others in 2012.

Another former Afghan soldier who murdered three Australia troops was also among the six.

The Taliban official said another two Taliban prisoners who murdered Frenchwoman Bettina Goislard, an employee of the UN refugee agency, had been released in Afghanistan's Wardak province.

Their release had also been initially opposed by Goislard's family and Paris. The Afghan government did not immediately confirm the claim.

The US-backed talks mark a major milestone in Afghanistan's 19-year conflict, but a peaceful outcome -- or even a ceasefire -- is far from guaranteed as negotiators grapple with wildly divergent goals.

"The talks are very likely to be long and arduous, easily taking years to complete, with many stops and halts, sometimes perhaps for months as fighting goes on," said Vanda Felbab-Brown, an Afghanistan expert and senior fellow at the Brookings Institution.

Any deal between the Afghan government and the Taliban will depend on both sides' willingness to tailor their competing visions for the country and the extent to which they can share power.

The Taliban, who have refused to recognise President Ashraf Ghani's government, will push to reshape Afghanistan into an Islamic "emirate".

Ghani's administration will seek to maintain the Western-backed status quo of a constitutional republic that has enshrined many rights including greater freedoms for women.

So far, the Taliban have only made vague pledges to protect women's rights through "Islamic values", and many Afghans fear any partial or full return to power would herald a resumption of previous policies such as executing women accused of adultery. 

- Claiming 'victory' -

The Taliban, who ruled most of Afghanistan from 1996 to 2001, will claim a stronger bargaining position than at any time since they were ousted.

They claimed victory in February after signing a deal with Washington that laid out a timetable for talks, which were supposed to start in March, and for foreign forces to withdraw by early next year.

In return, the Taliban offered security guarantees critics said were vague.

As soon as the ink dried on the deal, the insurgents unleashed fresh attacks on Afghan forces and have maintained a withering battlefield tempo.

The deal does not require the Taliban to formally renounce Al-Qaeda, the jihadist group formerly led by Osama bin Laden, which enjoyed safe haven in Afghanistan while plotting 9/11.

Instead, the Taliban must "not allow" such groups to use Afghanistan as a base.

"Posturing from the Taliban... suggests they perceive their current position to be one of great strength," said Andrew Watkins, an Afghanistan analyst with the International Crisis Group.

And while the Taliban have generally projected a unified front, the Afghan government has been riven by personal feuds and long-running rivalries.

- Ceasefire -

An immediate point of contention is expected to be the issue of stopping the bloodshed in a war that has killed tens of thousands of civilians and displaced millions more.

The US deal insisted the Taliban include a permanent truce only as "an item on the agenda" in negotiations, but Kabul insists it wants to push for a ceasefire from day one -- something the Taliban have said is a non-starter.

The Taliban "don't trust the United States or Afghan government enough to stop fighting, until peace talks reach a point that they believe their group may have genuinely secured their interests", Watkins said.

Still, Felbab-Brown said the Taliban would prefer a peace deal to having to fight for the rest of Afghanistan, particularly Kabul.

Even if the Taliban and the Afghan government eventually strike a deal, what comes next is an open question.

The US has stressed Afghanistan's future is now in Afghan hands and suggested that if a peace process breaks down and chaos ensues, so be it.

"Let's be clear: this isn't negotiating about peace. This is about the US getting out," said Christine Fair, a South Asia expert at Georgetown University.