Police in Yemen's second city Aden said on Wednesday that the bodies of 11 people with their throats cut had been found dumped in a nature reserve.
Aden is the headquarters of Yemen's Saudi-backed government but its forces have struggled to secure the city against repeated attacks by jihadists of both Al-Qaeda and the Islamic State group.
The bodies were found on Tuesday in the Al-Hiswa nature reserve on the city's western outskirts and are believed to have been killed more than a month ago, a security official said.
"The bodies were already decomposing and their throats had been cut," the official said.
Despite the intervention of a Saudi-led coalition in March last year in support of the Yemeni government, Shiite rebels and their allies remain in control of the capital Sanaa and much of the north.
The persistent insecurity in Aden prompted the government to operate from exile in neighbouring Saudi Arabia for nearly a year before setting up base in the city in September.