Suspected al Qaeda militants killed 19 soldiers in a rocket attack and suicide bombing on Saturday that targeted intelligence headquarters in the main southern city of Aden, a security official said.
"The death toll has increased to 19 soldiers while nine soldiers and three civilians were wounded," the official told AFP.
A medical source confirmed the toll.
The security official had said earlier that three soldiers were killed by a "car bomb driven by (a) suicide bomber into the courtyard of the intelligence building," while the others were killed in a rocket and gun attack.
"The attack is the work of al Qaeda elements," he said, requesting anonymity.
The same official had said that masked gunmen "used machineguns and rocket-propelled grenades" in the attack in the Tawahi coastal neighbourhood of Aden.
The militants 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 that many of the soldiers were asleep when the militants hurled hand grenades into their room.
Nine soldiers were wounded, and three television employees, among them two women, were also hurt, he said.
The militants managed to escape.
Witnesses said they saw two armoured vehicles on fire at the gate of the television offices.
Al Qaeda militants remain active in southern Yemen, where separatist militants also attack security forces, pressing their demands for renewed independence for the south.
South Yemen was a separate state before unification with the north in 1990.