Armed tribesmen killed 18 Houthi fighters in an ambush in Yemen's central province of Ibb on Tuesday, residents said, in one of the deadliest ground attacks in over two months of war.
The attack hit a convoy of militiamen and allied army troops in the town of Qaeda while they were en route to the city of Taiz, a flashpoint of clashes between Yemen's dominant Houthis and armed backers of exiled President Abd-Rabbu Mansour Hadi.
A coalition of Arab countries led by Saudi Arabia, seeking to restore Hadi to power, has carried out over nine weeks of airstrikes on Houthi fighters who have seized large parts of Yemen.
The Houthis, hailing from Yemen's far north, seized the capital in September and fanned out southward, triggering the Arab military intervention.
They describe their spread as a revolution and a victory against corruption, but Sunni Muslim Gulf Arab states worry that they are a proxy for the influence of their regional Shi'ite rival Iran.
Saudi-led airstrikes hit Houthi positions along Yemen's far northern border with the kingdom and struck military bases aligned with the group in the capital Sana’a on Tuesday.
Neighboring Oman, a neutral power, is mediating talks between Houthi and American officials in the capital Muscat aimed at ending Yemen's conflict.
The dialogue also led Yemeni authorities to release to Oman Monday a detained American freelance journalist.
Yemeni politicians said the discussions are narrowing ground between Yemen's exiled government and the Houthis and may soon pave the way for more formal United Nations-backed negotiations.