Yemen's warring parties have discussed forming military and security committees to oversee a transition period aimed at ending 14 months of fighting, the UN special envoy said Wednesday.

"Discussions continued on security and military issues, including the details of military and security committees," Ismail Ould Cheikh Ahmed said in a statement.

Peace talks in Kuwait between Iran-backed rebels and the government of President Abedrabbo Mansour Hadi have completed their eighth week without any major breakthrough other than the release of some prisoners.

Shiite Huthi rebels have announced the release of 187 prisoners and Saudi Arabia, which backs Hadi's administration, said last week it freed 52 children.

The UN envoy had tried to push the two sides to release half of all their prisoners before the Muslim fasting month of Ramadan, which began on June 6.

Yemen's foreign minister and the head of the government delegation Abdulmalek al-Mikhlafi threatened to pull out of the talks in a week's time if the "Huthis continue to reject peace".

"I think we still have another week... I believe we will reach the end," Mikhlafi told Sky News Arabia overnight when asked how long will they stay in Kuwait.

"Not only the government delegation, but also the ambassadors of countries (supporting the peace process) and the UN special envoy will leave," he said.

Mikhlafi said nothing has been achieved since the talks began on April 21 and "we have been revolving in a vacuum".

The main sticking point in talks remains the form of the government that would oversee a transition back to normality once a peace deal is reached.

The rebels and their allies have held out against demands contained in a UN Security Council resolution for their surrender of heavy weaponry and withdrawal from areas, including the capital, which they seized in September 2014.

The head of the Huthi delegation Mohammed Abdulsalam said late Tuesday that they would reject any deal that excludes their input on the make-up of the transitional body.

"Any deal that does not meet our demands of forming a consensual authority... will be rejected," he told Yemeni media.

This should include Huthi agreement on the president, the national unity government and military and security committees, he said.

The government has resisted proposals for a unity administration with the rebels, fearing it would undermine the international legitimacy of Hadi.

The war in Yemen has killed about 6,400 people, with more than 80 percent of the population in desperate need of humanitarian aid, according to the UN.

On ground, nine rebels were killed in a late Tuesday air raid by the Saudi-led coalition on the northern Jawf province, a Huthi stronghold, military sources said.

Meanwhile, eight other rebels and six pro-government soldiers were killed in 24 hours of fighting in the southern province of Daleh, controlled by loyalists, the sources said.