The clashes erupted on Tuesday, when the pro-Hadi tribesmen attacked several bases and checkpoints of Ansarullah fighters. The fighting left 15 Houthi fighters and nine tribesmen dead.

In Marib, east of the capital, Sana’a, six tribesmen loyal to Hadi, including a tribal chief, were killed in clashes with Ansarullah fighters late on Monday.

Ta’izz violence

Meanwhile, an anti-Houthi protest in the southern city of Ta’izz turned violent, leaving five people dead and dozens more injured.

Ansarullah fighters on Sunday took control of Ta’izz, a strategic city between the capital Sana'a and Aden, where Hadi has been based over the past weeks.

The Ansarullah fighters seized the airport in Ta’izz after defeating forces loyal to the fugitive president. They also captured several state facilities including a court complex in Yemen’s third largest city.

Ansarullah fighters also sent reinforcement to an area in the neighboring province of Ibb, northeast of Ta’izz.

In late January, Hadi, along with the cabinet of Prime Minister Khaled Bahah, stepped down over pressure from the Ansarullah revolutionaries, but the Yemeni parliament did not approve his resignation.

Hadi fled his home in the capital on February 21 after weeks under effective house arrest and went to Aden, Yemen’s second largest city, where he officially withdrew his resignation and highlighted his intention to resume duties.

The Ansarullah fighters took control of the capital in September 2014 and are currently trying to advance toward Aden.