(Adds details, background)
ADEN, Sept 30 (Reuters) - At least three Yemeni soldiers were killed and six wounded on Monday when a group of suspected al Qaeda militants disguised as security personnel seized an army base in the southeastern city of al-Mukalla, a military official said.
The official said dozens of militants stormed the headquarters of the Yemeni army's Second Division and captured some military personnel.
"They caused confusion because soldiers at the base thought they were being attacked by members of the Central Security apparatus," the official said.
A resident said he heard several big explosions and that the army cordoned off the area leading up to the military base.
Yemen is battling one of the most active branches of al Qaeda, known as al Qaeda in the Arabian Peninsula (AQAP), which has carried out a number of foiled attempts to attack U.S. targets, including airliners.
On September 20, suspected al Qaeda militants killed dozens of Yemeni soldiers and policemen in attacks in the south of the country, which officials described as the deadliest for more than a year. [ID: nL5N0HG13V]
Dozens of Yemeni security and military officers have been killed in the past two years, many by bombs planted in their cars or drive-by shootings, often blamed on al Qaeda in the Arabian Peninsula or affiliated groups.
Intelligence pointing to an impending attack by AQAP prompted the United States and other Western countries to close many of their embassies temporarily in the Middle East, Africa and Asia last month.
The militants took advantage of political chaos in Yemen during the Arab Spring in 2011 to seize control of some towns and surrounding areas in the south of the country.
They were beaten back by Yemeni forces with assistance from the United States and scattered into small groups spread across the country's rugged, remote southern terrain. (Reporting by Mohammed Mukhashaf; Additional reporting by Mohammed Ghobari; Writing by Mahmoud Habboush; Editing by Angus MacSwan)