(Updates death toll, adds details, background)
ADEN, Yemen, May 24 (Reuters) - At least 27 people were killed in an overnight raid by dozens of al Qaeda militants on Yemeni government buildings and military posts in Seyoun, the second largest city in the south-eastern Hadramout province, a local official and residents said.
The gunmen targeted the main military posts, the local police headquarters and bank branches and briefly captured some buildings before they withdrew in the morning, they said.
Al Qaeda has conducted many hit-and-run attacks since the Yemeni army drove it from its strongholds in Abyan and Shabwa provinces, also in the south, last month.
Gulf Arab countries and the United States are concerned about violence in Western-allied Yemen, a neighbour of major oil exporter Saudi Arabia and home to one of al Qaeda's most active wings.
The militants arrived in 15 pickup trucks from desert areas outside Seyoun and proceeded to attack various government buildings, a local security official said.
"They wanted to capture the city and control it," the official, who asked not to be named, told Reuters.
The official put the death toll among the militants at 20, saying they took away 18 bodies. Five members of the security forces and two soldiers died in the fighting, he said. (Reporting by Mohammed Mukhashaf; Writing by Sami Aboudi; Editing by Robin Pomeroy)