ISLAMABAD (AP) — Pakistan, Afghanistan and the United States on Wednesday discussed how to provide Taliban leaders safe passage to join peace negotiations, a key issue to allow the talks to succeed, officials said.

Many senior Taliban commanders, including leader Mullah Omar, are believed to be based in Pakistan, making Islamabad's cooperation critical. Pakistan also has strong historical ties with the group that many analysts believe have continued.

The U.S. and Afghan governments have urged Islamabad to push the Taliban to participate in a peace process that has had trouble getting off the ground. All three countries believe a peace deal is necessary to prevent Afghanistan from descending into civil war after most foreign forces withdraw by the end of 2014. But the process has been plagued by mistrust between the three governments and the Taliban.

The discussions that took place Wednesday in the Pakistani capital, Islamabad, marked the inaugural meeting of the Safe Passage Working Group, said the Pakistani Foreign Ministry in a written statement. The three governments agreed to form the group in April, the ministry said.

The group is focused on choosing which Taliban leaders should be provided safe passage, guaranteeing their security and dealing with logistics like visas, said a U.S. official, speaking on condition of anonymity because the official was not authorized to talk to reporters about the meeting. The official described the meeting as "positive."

The U.S. began clandestine talks with the Taliban last year, aided by Germany and secretly held in Qatar. It is widely believed that Pakistan provided safe passage to some Taliban militants to attend those discussions.

But the contacts have run into a series of problems.

The Taliban broke off talks earlier this year, saying the U.S. reneged on a promise to release Afghan prisoners from Guantanamo Bay, the U.S. security prison in Cuba. To get the Taliban back to the table, the U.S. has said it is considering a proposal to transfer some Guantanamo Bay inmates to a prison in Afghanistan.

The Taliban have said they want the prisoners freed unconditionally before resuming talks.