Negotiators from Afghanistan, China, Pakistan and the United States met in Oman on October 16 to try to find ways of reviving peace talks with the Afghan Taliban.
It was not clear whether any Taliban militants had joined the talks, which have so far failed to restart a peace process that collapsed in 2015.
Taliban sources have said they would stay away from the discussions in Muscat, casting doubt on prospects for reviving the long-stalled negotiations.
Pakistani officials said the talks had resumed on Pakistan's initiative. The Pakistani team was led by Foreign Secretary Tehmina Janjua.
The Afghan team, led by Deputy Foreign Minister Hekmat Khalil Karzai, said the talks would focus on relations between Pakistan and Afghanistan and implementing Pakistan's commitments to fight terrorism.
In Washington, a State Department official confirmed the meeting on October 16 took place but declined to provide any details. There was no immediate comment from China.
The four-nation Quadrilateral Coordination Group, which last met in Islamabad in early 2016, has been trying to open a path to direct talks between the Afghan government and the Taliban, with little success.
Amin Waqad, a close aide to Afghan President Ashraf Ghani and a senior member of the High Peace Council, said last week his country would participate in the Muscat meeting and that the Taliban representatives would also be there.
The Taliban denied that they had received any invitation.
The principal obstacle to negotiations has been the Taliban's refusal to attend after their last leader, Mullah Akhtar Mansur, was killed in a U.S. drone strike in Pakistan last year.
The United States wants Pakistan, which it accuses of harboring Afghan Taliban commanders, to exert more influence on the militants to bring them to the negotiating table.
Pakistani officials deny sheltering Taliban militants and say their influence on the group has waned.