Forces loyal to former Yemeni President Ali Abdullah Saleh battled their former Houthi allies on Thursday over control of a key outpost, marking the first such battle between the two sides since the veteran leader was killed last year.

Yemen’s armed Houthi movement said on Wednesday it had launched a drone strike on a facility belonging to oil giant Saudi Aramco in southern Saudi Arabia - though the company said its plants there were operating “normally and safely”.

Yemen’s Houthi forces shot down a U.S. surveillance drone in the capital Sanaa on Sunday, the Houthi-controlled state news agency SABA reported.

Yemen’s Houthi leader Abdel-Malek al-Houthi said on Thursday his group could target Saudi oil tankers should Saudi Arabia attack Yemen’s main port at Hodeidah.

The Saudi-backed Yemeni government will not allow its Houthi foes to keep the Red Sea port of Hodeidah, the information minister said, underlining its intention to remove the vital aid delivery point from the control of the Iran-aligned group.