SANAA (Reuters) - Tribal fighters backed by a Saudi-coalition won control of a strategic dam in central Yemen from Houthi forces on Tuesday but lost ground in the south near the port of Aden, where President Abd-Rabbu Mansour Hadi's government is based, residents and officials said.
The seizure of the Marib dam by militiamen fighting alongside Gulf troops is their biggest success in several weeks of an armed push toward the Houthi-controlled capital Sanaa 110 km (70 miles) West that was slowed by landmines and stiff resistance from Houthi forces ensconced in rugged mountains.
Pictures printed on the front pages of Gulf dailies showed the foreign troops and local tribesmen planting the flags of the United Arab Emirates, Bahrain and Saudi Arabia over the dam.
A coalition of Arab states has been attacking the Iran-allied Houthis across Yemen since March, trying to dislodge it from areas it has seized since last year and to Hadi.
Arab Gulf countries see their intervention as a part of a wider struggle by Sunni states against what they see as meddling by Shi'ite Iran, a charge Tehran denies.
Condemning Hadi's government as a tool of the Gulf monarchies and the imperialist West, the Houthis say their spread through the country is a revolution.
The Saudi-led campaign seized Aden and other southern provinces from the Houthis in July but has struggled to take over other population centers and cement their authority in the increasingly lawless region.
In pro-Hadi fighters' first significant loss in weeks, a district in the southwestern Taiz province fell to the Houthis and their allies in Yemen's army on Tuesday.
Residents and local officials also said they appeared to be mobilizing their forces for a southern push in the nearby area of Kirsh, about 75 km (46 miles) from Aden.
Six months of civil war and hundreds of coalition air strikes have killed more than 5,400 people in Yemen, according to the United Nations, and exacerbated already widespread hunger and suffering.
The Saudi-led coalition again denied responsibility for an air strike on a wedding party in Taiz province on Monday which medics said killed 131 people, in one of the deadliest attacks on civilians in the war.
"No air strikes were launched in that area in the past three days...it's not true that every explosion that happens in Yemen is caused by the coalition," alliance spokesman Brigadier General Ahmed Asseri said in comments carried by the UAE's state news agency WAM.
Residents in the village of al-Wahijah said that two missiles blasted through tents where a local man affiliated with the Houthi group was holding his wedding reception.
(Reporting By Mohammed Ghobari, Writing by Noah Browning, Editing by Angus MacSwan)