A traditional council is to open on Friday in the Afghan capital to decide the release of a final 400 Taliban -- the last hurdle to the start of negotiations between Kabul''s political leadership and the Taliban in keeping with a peace deal the United States signed with the insurgent movement in February.

The negotiations are a critical step toward lasting peace in Afghanistan. The talks will decide what a peaceful Afghanistan might look like, what constitutional changes will be made, how the rights of women and minorities will be protected and the fate of the tens of thousands of heavily armed men on both sides of the conflict.

As well as Taliban fighters, warlords in Kabul maintain thousands of armed militias loyal to them.

The US in a statement issued late on Wednesday said it welcomed the traditional council, or jirga, but US Secretary of State Mike Pompeo also seemed to make it clear that the 400 prisoners had to be released if peace talks with the Taliban were to move forward.

“We acknowledge that the release of these prisoners is unpopular,” Pompeo said in the statement. “But this difficult action will lead to an important result long sought by Afghans and Afghanistan''s friends: reduction of violence and direct talks resulting in a peace agreement and an end to the war."

The statement would indicate that Washington was not ready to accept a decision to deny the 400 Taliban their freedom.

Pompeo, who held a video call with the Taliban''s chief negotiator, Mullah Abdul Ghani Baradar earlier this week, also said that the Taliban had agreed to a reduction of violence once talks began.

Taliban political spokesman Suhail Shaheen said previously that a permanent cease-fire could be one of the first items on the agenda of negotiations between the Taliban and Kabul''s leadership.

“The Taliban have also committed to significantly reduce violence and casualties during the talks where the parties will decide on a political road map to end the long and brutal war and agree on a permanent and comprehensive ceasefire,” Pompeo said.

“The United States intends to hold the Taliban to these commitments.”

Since signing the agreement with Washington in February, the Taliban have not attacked US and NATO troops but have continued to wage war with the Afghan National Security Forces.

The US and NATO have also begun withdrawing some troops in line with the agreement.

The February peace deal calls on the Taliban to guarantee Afghanistan will not be used as a staging arena by terrorist groups to attack the United States or its allies. The withdrawal of US and NATO troops hinges on the Taliban meeting those commitments and not on a positive outcome of the negotiations between the Taliban and Kabul''s political leadership.

The intra-Afghan negotiations that Washington had hoped would begin in March have been delayed by the reluctance of Kabul to release the Taliban prisoners.

The deal called on Kabul to free 5,000 Taliban and the insurgent group to free 1,000 government and military personnel. Political squabbling in Kabul between President Ashraf Ghani and his rival Abdullah Abdullah over the result of presidential polls last year initially delayed movement on the agreement.

The two men eventually settled on a compromise and Abdullah was put in charge of the peace negotiations as head of the High Council for National Reconciliation.

Ghani eventually freed all but 400 of the 5,000 Taliban while insisting on a council to decide whether they could be released saying their crimes, which included killings, were too serious for him to decide alone.

Pompeo''s statement, however, seemed clear on which side Washington wanted the council to decide.

“The United States urges President Ghani and Dr Abdullah, the Chairman of the High Council for National Reconciliation, and other Afghan leaders, including participants of the Loya Jirga, to take advantage of this historic opportunity for a peace that benefits all Afghans and contributes to regional stability and global security,” the US State Department said.