Gunmen have attacked the headquarters of Yemen's Political Security Service in the southern city of Aden.
At least two members of the security forces were killed. Unconfirmed reports said up to 13 people, including 10 security personnel, were left dead.
There were heavy exchanges of gunfire and smoke is still rising from inside.
Local officials blamed the raid on al-Qaeda, which has urged supporters to take up arms against the government in response to a crackdown in the east.
