STC separatists accuse Saudi Arabia of requiring flights to UAE to land in Jeddah; Saudi source rejects claim.

Flights from Aden international airport in Yemen were halted on Thursday amid continuing tensions between the Southern Transitional Council (STC) separatist group and the Saudi Arabia-backed internationally recognised government in Yemen.

Reuters news agency reported that all flights were suspended at the airport on Thursday, although further details of flight operations and possible resumptions remained unclear.

The STC has formally been a part of the Saudi-led coalition that, since 2015, has been fighting the Houthi takeover of large parts of Yemen. But the STC also seeks to carve out a separate nation in southern Yemen, and in December, expanded its military operations in Hadramout and al-Mahra provinces that border Saudi Arabia, setting off a rapid escalation in tensions.

Saudi Arabia has accused the United Arab Emirates – also a part of the anti-Houthi coalition – of arming the STC and of encouraging the separatist group to expand into Hadramout and al-Mahra, which Riyadh has said threatens its national security. The UAE has denied those allegations, insisting that it supports Saudi Arabia’s security.

However, while the UAE has since agreed to demands from Yemen’s Riyadh-backed Presidential Leadership Council and Saudi Arabia to withdraw its troops from Yemen, the STC has refused to pull back from Hadramout and al-Mahra.

On Thursday, the STC-aligned Transport Ministry within the internationally recognised government claimed that the stoppage at the airport was a result of Saudi Arabia imposing new requirements mandating that flights to and from Aden airport undergo inspection in Jeddah.

The ministry said it was “shocked” by the move, adding that Saudi authorities later clarified the restriction only applied to flights operating between Aden and the United Arab Emirates.

A Saudi source denied to the Reuters news agency that it was involved in restricting flights, saying Yemen’s internationally recognised government, led by the Presidential Leadership Council, was behind the requirement for UAE-bound flights.

Yemeni presidential adviser, Thabet al-Ahmadi, confirmed to Al Jazeera that it had imposed a requirement that applied to one flight route departing from Aden airport. He said the move was meant to prevent STC money smuggling.

Al-Ahmadi said the government did not support a complete halt to flights, adding it wanted to ensure air traffic continued unimpeded.

Earlier this week, the UAE announced it was voluntarily withdrawing its remaining “counterterrorism” forces from Yemen. That came after Riyadh struck what it claimed to be a UAE-linked weapons shipment in the southern port city of Mukalla.

On Wednesday, Rashad al-Alimi, the head of the internationally recognised government in Yemen, warned that any moves by the STC to further entrench their position in the provinces would have severe consequences.

The STC has, however, remained defiant, saying it would remain in the provinces.

However, STC spokesperson Mohammed al-Naqeeb said the group was coordinating its movements with the Homeland Shield forces, which had been the main security force in the provinces prior to the STC offensive. The Homeland Shield is affiliated with the Yemeni government and the Saudi-led coalition.

Yemen has been embroiled in a civil war since Houthi forces took control of the capital Sanaa in 2014. The group continues to control large swaths of the country’s northwest, with the STC and government contesting the southern and eastern flanks.