Air strikes by the Saudi-led coalition killed seven separatist fighters in Yemen on Friday, according to an official from the group, as the coalition responded to rapid territorial gains by the UAE-backed Southern Transitional Council (STC), raising fears of a wider confrontation.

The strikes mark the first reported deaths caused by coalition fire since the STC seized large parts of Hadramawt and Mahra provinces last month.

An STC spokesperson said the group was engaged in a “decisive and existential” battle with Saudi-backed forces. Mohammed Abdulmalik, head of the STC in Wadi Hadramawt and the Hadramawt Desert, said seven air strikes hit the Al-Khasah military camp, killing seven fighters and injuring more than 20 others. He added that additional strikes targeted other locations in the region.

The air raids followed a move by pro-Saudi forces to begin what they described as a “peaceful” campaign to take control of military sites in Hadramawt.

Separately on Friday, Saudi Arabia’s ambassador to Yemen, Mohammed Al-Jabir, accused the STC of blocking a Saudi delegation from landing at Aden airport, describing the group’s actions as “intransigent.”

A day earlier, Yemen’s STC-controlled transport ministry criticised a Saudi demand requiring all flights to and from the United Arab Emirates to make a stop in Saudi Arabia for security checks.