AL-MUKALLA: Yemeni government negotiators said they will boycott any further UN-mediated negotiations with the Houthis over prisoner exchanges until the militia reveals the whereabouts of detained politician Mohammed Qahtan and allows his family and government officials to visit him.

In a message posted on Twitter, Hadi Haig, head of the government delegation involved in the talks, said: “Our position is clear: We will not participate until this visit takes place. We hope that the (UN) envoy’s office will exert pressure in this regard to advance this file.”

Qahtan, a prominent Yemeni politician, was forcibly disappeared eight years ago by the Houthis, who have ignored repeated demands by the UN Security Council, local and international rights groups, and the politician’s family for his release.

The reluctance of the Houthis to allow relatives to visit him, or disclose his whereabouts, have fueled concerns that he might have died in custody.

During a first round of prisoner-swap negotiations in March, the Yemeni government and the Houthis agreed to exchange more than 900 prisoners and grant each other access to prisons in Marib and Sanaa. The two sides were due to reconvene after those visits for a second round of negotiations in the hope of negotiating the release of a larger number of prisoners.

However, members of a government delegation that was due to visit Houthi jails said they were denied permission to see Qahtan. As a result, they canceled their visit and suspended their participation in talks with the militia.

Meanwhile, the Houthis said government “preconditions” had delayed their own delegation’s visit to a government-run prison in the central city of Marib.

The government delegation’s suspension of talks with the Houthis comes as Hans Grundberg, the UN’s special envoy for Yemen, continues to travel between regional capitals in an effort to engage those involved in the conflict in talks to extend the UN-brokered truce and, ultimately, strike a peace deal.

Grundberg’s office said he arrived in Muscat on Monday where he met Omani officials and Houthi senior negotiator Mohammed Abdulsalam to “explore ways to advance the progress of ongoing peace efforts.”

The envoy previously visited Riyadh where he met, with the same aim, the Saudi ambassador to Yemen, Mohammed Al-Jaber; the ambassadors to Yemen of the five permanent members of the UN Security Council (the US, the UK, France, Russia and China); Rashad Al-Alimi, the head of Yemen’s Presidential Leadership Council; and other leading Yemeni officials.

In an interview with China Global Television Network last week, Grundberg said a lasting cease-fire in Yemen “is conceivable in the near future” but will require a great deal of effort, concessions from the warring factions, and international support.

“I do believe that that is possible but I would not want to say that it is going to be easy,” he added. “It still requires compromises to be made from the parties in order to reach that level of agreement.

“We’re in a position right now where there are ongoing discussions taking place on different levels in support of the UN mediation efforts.”