A suicide car bomber killed 12 soldiers and wounded six others Friday in an attack on a military command centre in southern Yemen's Abyan province, security and military sources said.
The attack in the district of Ahwar targeted the command centre of the 111th Brigade, the security source said, adding that the commander of the brigade was "seriously" wounded in the blast.
The sources gave an initial toll of six dead, but said later that it had doubled to 12. The commander was still among the six wounded.
The military source said the bomber had used an armoured vehicle to carry out the attack.
There was no immediate claim of responsibility.
On Thursday gunmen suspected of membership in Al-Qaeda carried out two attacks targeting a police post and a security checkpoint near Abyan, military sources said.
A soldier was killed and two others wounded in the attack on the security checkpoint, they added.
Suspected Al-Qaeda fighters carry out frequent attacks in southern Yemen, a lawless region where jihadist groups are active.
On Tuesday a police officer was gunned in a motorcycle drive-by shooting in Hadramawt province.
Last month a gun battle in Abyan province left two suspected Al-Qaeda militants and a pro-government militiaman dead, after a failed attack on the head of a militia that backs the government.
The militias, who recruit from the area's heavily armed tribes, fought a fierce war alongside the army in mid-2012. They helped to drive Al-Qaeda militants out of the main cities of Abyan, after the extremist network had held them for a year.
Al-Qaeda in the Arabian Peninsula (AQAP) has intensified its attacks on security forces in Yemen, taking advantage of the weakening of the Sanaa central government since a popular uprising that toppled president Ali Abdullah Saleh in 2011.