Yemen’s Houthi group launched two drone attacks on Saudi Arabia’s southern Abha airport, the Iran-aligned group’s military spokesman said on Thursday, Trend reports citing Reuters.

There was no immediate confirmation from the Saudi-led coalition fighting the Houthis in Yemen.

Al Masirah TV’s Twitter feed quoted the Houthi military spokesman Yahya Saria as saying the attack on Abha airport targeted the monitoring tower and other sensitive locations, adding that air traffic was disrupted.

The Houthis, who control Sanaa, the Yemeni capital, in the past few months have stepped up their attacks against targets in Saudi Arabia. In response, the coalition has targeted military sites belonging to the group, especially around Sanaa.

The escalation in violence threatens a U.N.-sponsored deal for a ceasefire and troop withdrawal from the flashpoint coastal city of Hodeidah, which became the focus of the war last year when the coalition tried to seize its port, the Houthis’ main supply line and a lifeline for millions of Yemenis.