Suspected al-Qaeda fighters have killed at least 20 Yemeni intelligence officers and security guards, and injured 13 others in a grenade attack that targeted intelligence headquarters in the southern city of Aden, medical officials said.
More bodies were believed to be buried under the rubble of the building, part of which was levelled in the attack, the ministry said on its website on Saturday.
A defence ministry official told the AFP news agency that masked gunmen "used machine guns and rocket-propelled grenades" in the attack in the Tawahi coastal neighbourhood of Aden.
Witnesses said fighters fired the grenades at the intelligence service's three-storey building, shattering windows and setting it on fire.
The ministry said all the casualties were members of the intelligence service and the Central Security forces, which guard the nearby television offices.
The defence ministry source said the attack was the work of al-Qaeda.
Television employees injured
The fighters attacked in two groups, with one targeting the south side of the complex and the other attacking the west side, next to the state television building.
The official said many of the soldiers were asleep when the fighters hurled hand grenades into their room.
Nine soldiers were wounded, and three television employees, among them two women, were also hurt, he said.
The fighters, however, managed to escape.
Witnesses said they saw two armoured vehicles on fire at the gate of the television offices.
Fighters have carried out a series of deadly suicide bombings on high-profile military and security targets since June, attacking a police academy in Sanaa, assassinating the commander of the southern region, and trying to kill the commander of a tribal force allied with the army.
The United States has been pouring aid into Yemen, and has stepped up its drone strikes on al-Qaeda in the Arabian Peninsula (AQAP), to stem the threat of attacks from AQAP and to try to prevent any spillover of violence into neighbouring Saudi Arabia.
Last year, a US-backed offensive drove out al-Qaeda offshoot Ansar al-Sharia (Partisans of Islamic Law) from cities they had seized in an uprising against former president Ali Abdullah Saleh.