Six Shiite Huthi militants were killed in an attack in central Yemen on Friday, tribal sources said, as Al-Qaeda claimed it had killed dozens.
Ansarullah militiamen, also called Huthis, have captured many communities in western and central Yemen since taking the capital Sanaa on September 21.
But they have been met by fierce resistance from Sunni tribes and Al-Qaeda militants.
Tribal sources told AFP that "unknown gunmen" killed six militiamen at a Huthi checkpoint in the central province of Baida, the scene of deadly fighting between the group and Al-Qaeda.
Al-Qaeda in the Arabian Peninsula (AQAP) said on Twitter on Friday it had killed "70" Huthi militiamen in several attacks in Rada, in Baida province.
AFP could not confirm the toll from independent sources or from Ansarullah, which rarely acknowledges its casualties.
AQAP military chief Qassem al-Rimi vowed in November to launch fierce attacks against the militiamen.
"To the Huthis we say: brace yourselves for horrors that will make the hair of children turn white," he said.
AQAP, considered by Washington as the most dangerous arm of the jihadist organisation, said several of its attacks targeting Huthis were only a "warm-up".
AQAP leader Nasser al-Wuhayshi has accused the Huthis of collaborating with the United States and Iran to destroy Sunni Muslims.