Stakes are high for both sets of talks. Washington has said it wants to seal a political deal with the Taliban ahead of Afghan presidential polls due in September to allow foreign forces to begin to withdraw.

Security was tight at the luxury hotel hosting the intra-Afghan summit as around 70 delegates, who were required to surrender their phones, ushered into the hall and sat in a vast semi-circle facing a large video screen and the hosts from Qatar and Germany.

"Gathered around the table today are some of the brightest minds representing a cross-section of Afghan society," said Markus Potzel, Germany's special representative for Afghanistan and Pakistan, as he opened the gathering.

"Each of you will have a unique opportunity and a unique responsibility to find ways of turning violent confrontation into a peaceful debate."

Taliban negotiator Abbas Stanikzai had a brief altercation with a security guard as he attempted to enter the secure conference area.

"We want to go to the dialogue but they are not letting us," Stanikzai said to an officer who replied "we are not joking with you, stop shouting at us".

But he and the rest of the Taliban delegation, which included Suhail Shaheen, the group's Doha office spokesman, took their seats in the expansive ballroom shortly before the talks began at 0630 GMT.

- Talks in 'personal capacity' -

The Qatar foreign ministry special envoy on counterterrorism Mutlaq al-Qahtani said: "We are so happy to see all our Afghan brothers and sisters meeting here in Doha."

"We want a roadmap for the future of Afghanistan," he told reporters after the hosts left the Afghan parties with mediators to begin discussions.

The so-called intra-Afghan dialogue follows six days of direct US-Taliban talks that have been put on hold for the two day Afghan conference and are set to resume Tuesday, according to both sides.

US lead negotiator Zalmay Khalilzad said Saturday that the latest round of US-Taliban talks "have been the most productive of the rounds we've had with the Talibs".

"Essentially the four items we have been talking about ever since we started (are) terrorism, withdrawal of foreign troops, inter-Afghan negotiations and dialogue, and ceasefire," Khalilzad told AFP.

"For the first time I can say we have had substantive discussions, negotiations, and progress on all four issues."

Shaheen, the Taliban spokesman in Qatar, said they were "happy with progress... We have not faced any obstacles yet".

Leading figures are attending the separate intra-Afghan talks, including political heavyweights, government officials, at least six women and other Afghan stakeholders.

The United States is not participating directly in the two-day summit although Khalilzad did pass by the hall hosting the Afghan talks without pausing to speak to the press.

The Taliban, who have steadfastly refused to negotiate with the government of President Ashraf Ghani, have stressed that those attending are only doing so in a "personal capacity".

Ghani's administration, which the Taliban consider a puppet regime, has also been excluded from the direct US-Taliban talks.

Sunday's gathering is the third such meeting following similar summits in Moscow in February and May.

- 'Friendly' talks -

The first encounter marked a historic breakthrough and saw the Taliban hear the opinions of the two women attendees before laying out their constitutional and political programme on live TV for the first time.

An agreement with the Taliban is expected to have two main points -- a US withdrawal from Afghanistan and a commitment by the militants not to provide a base for terrorists, the main reason behind the US invasion nearly 18 years ago.

But the thorny issues of women's rights, power-sharing with the Taliban, the role of regional powers including Pakistan and India, and the fate of Ghani's administration remain unresolved.

The Taliban, believing they have the upper hand in the war, have kept up attacks even while talking to the United States and agreeing to the Afghan dialogue.

A Taliban car bomb in eastern Afghanistan killed at least 12 people and wounded scores more on Sunday, officials said.

Despite the violence, both the Taliban and US have been positive about their engagement.