Yemen's Huthi rebels said Wednesday they were stranded in the capital Sanaa on the eve of United Nations-sponsored peace talks in Geneva with their government rivals.
The Huthis said the UN had been unable to "secure authorisation" from a Saudi-led coalition backing the government for a plane to transport the rebel delegation and wounded insurgents out of the country, according to the Huthis' Al-Masirah TV.
While the Huthis control Sanaa and much of northern Yemen, the coalition controls the country's airspace.
The Huthis, who are linked to Saudi Arabia's arch-nemesis Iran, have hinted that their delegation demanded the evacuation of wounded rebels to Oman for medical treatment as a condition for their attendance at the talks.
Huthi spokesman Mohammed Abdulsalam tweeted on Tuesday that the UN had "made promises on facilitating the transport of the wounded... abroad" and accused the world body of stalling.
In 2014, the Huthis seized Sanaa, driving the government of Abedrabbo Mansour Hadi into exile and marking a major turning point in Yemen's long-running conflict.
The following year, Saudi Arabia and its allies formed a powerful regional military coalition to back the Hadi government in its fight against the Huthis.
Nearly 10,000 people have been killed since the Saudi-led alliance joined the war, pushing the impoverished country to the brink of famine.
The last round of peace talks between the Huthis and government collapsed in 2016, when 108 days of negotiations in Kuwait failed to broker a power-sharing agreement.
The Huthi delegation to Kuwait was grounded in Oman for three months on its way back to Yemen, blocked from travel by the Saudi-led coalition.