A dispute between the Yemeni legitimate government and Iran-backed Houthi militias over details of the two-month truce agreement led to the delay of the first scheduled flight out of Sanaa on Sunday.
The flight was set to fly to the Jordanian capital, Amman.
The government accused the Houthis of violating the truce and attempting to add travelers, whose identity could not be confirmed, on to the flight. It charged that they were holding illegal passports.
Information Minister Moammar al-Iryani said the Houthis did not adhere to the agreement because they wanted dozens of passengers to board using illegal passports.
He said the government allowed the travel of 104 passengers on the Sanaa-Amman flight but the Houthis insisted on adding 60 more passengers "with unreliable passports."
He cited reports that said the Houthis were planning to use the flights to smuggle out dozens of their leading members and experts from the Iranian Revolutionary Guards and Lebanese Hezbollah party.
He called on the international community, UN and UN envoy Hans Grundberg to pressure the Houthis to cease their meddling in this humanitarian file and to stop using citizens living in areas under their control as hostages to achieve their interests.
The Houthis, for their part, criticized the failure to operate the flight, saying it was a violation of the truce.
The militias have been increasingly violating the truce on the ground for days. As of the weekend, the Yemeni military had confirmed 2,000 field violations since the announcement of the truce on April 2.
The truce had called for the operation of two flights per week to and from Sanaa airport from Amman and Cairo.
The truce also called for a nationwide ceasefire, the possibility of opening crossings and ending the Houthi siege on Taiz, and allowing 18 fuel ships to unload at Hodeidah port.
Grundberg urged both sides to "work constructively" with the UN to address the challenges that delayed the flight.
"The Truce is meant to benefit civilians including through reducing violence, making fuel available, and improving their freedom of movement to, from and within their country,” he said on Twitter.
The envoy's office said Grundberg began mediation efforts to address differences between the two sides on flight procedures when a disagreement arose on Thursday. It did not elaborate.
The legitimate government stressed its keenness on carrying out everything that would ease the humanitarian suffering of the people.
It said it had taken all the necessary measures to ensure the operation of the Sanaa flights in line with the truce agreement.
It added that it only recognizes passports that are issued by the legitimate authorities, meaning the Yemeni government alone.
It accused the Houthis of shutting the Sanaa ticket sales offices of the Yemenia airlines and of issuing passports to the travelers.
"Out of its keenness on the safety of procedures and commitment to the international community and destination countries, the government had, through the UN envoy's office, requested that the Houthis commit to the truce and drop the names of travelers who do not hold recognized passports," said the government.
The militias rejected the request and the flight was consequently delayed until they abide by the agreement.
The government stressed that it had provided facilitations to people living in Houthi-held regions to obtain passports from liberated regions.
