By Mohammed Ghobari
SANAA, Feb 14 (Reuters) - Tens of thousands of Yemenis demonstrated in several cities on Saturday against the rule of the Shi'ite Muslim Houthi movement whose gunmen fired on protesters in the central town of Ibb and wounded four, medics said.
It was the second day of nationwide demonstrations against the Iranian-backed Houthis in less then a week after its dissolution of parliament this month unraveled security and sent Western and Arab embassies packing.
Activists said they were enraged by the death on Saturday of Saleh al-Bashiri, who they say was detained by gunmen as they broke up an anti-Houthi protest in Sanaa two weeks ago and was released to a hospital with signs of torture on his body on Thursday. There was no immediate comment from the Houthis.
Yemen's upheaval has drawn international concern as it shares a long border with top world oil exporter Saudi Arabia, and the country is also fighting one of the most formidable branches of al Qaeda with the help of U.S. drone strikes.
Heavy clashes between Houthi fighters and Sunni Muslim tribesmen fighting alongside Al Qaeda militants in the southern mountainous province of al-Bayda on Saturday killed 16 Houthi rebels along with 10 Sunni tribesmen and militants, security officials and tribal sources told Reuters.
The state faces collapse in impoverished, strife-torn Yemen two weeks after the Houthis took formal control of the country and continued an armed push southward.
France, the United States, Britain, Germany, Italy and Saudi Arabia have closed their missions in the capital Sanaa and withdrawn staff, citing security concerns.
Spain and the United Arab Emirates announced the closure of their embassies in Sanaa on Saturday.
The United Arab Emirates' state news agency WAM cited "the increasing deterioration of the political and security situation Yemen is witnessing and the tragic events after the Houthis undermined the legitimate authority."
Yemen's rich Sunni Gulf Arab neighbors loathe the Houthi fighters and have called their rise to power a "coup."
The embassy closures have isolated Yemen's new rulers and lent urgency to struggling talks over internal power-sharing which the Houthis are conducting with opposition parties.
Hailing their advance as a "revolution" aimed at corrupt officials and economic ruin, the Houthis dissolved parliament and set up their own ruling body earlier this month.
The Houthis' spread from the north to Yemen's well-armed tribal regions in the east and south has led locals to make common cause with Al Qaeda in the Arabian Peninsula, one of the deadliest arms of the global militant organization.
(Writing by Noah Browning; Editing by Mark Heinrich)