A burned out car marks the site of a major car bomb by Shebab insurgents in Mogadishu, on August 31, 2014
Mogadishu (AFP) - Somalia's Shebab rebels carried out a car bomb and gun attack against an intelligence headquarters in central Mogadishu on Sunday, leaving at least seven militants and five others dead.
The Al-Qaeda-linked militia claimed responsibility for the raid against the complex, which also houses a major detention facility, saying it was being used for the "torture and humiliation" of "innocent Muslims".
The coordinated attack came a day after Somalia's national army and African Union forces said they had captured a Shebab stronghold as part of a joint offensive aimed at seizing key ports and cutting off an important source of revenue for the Islamist rebels.
In Sunday's attack, police and witnesses said a car bomb was detonated outside the National Intelligence Centre and was followed by a raid by gunmen disguised in national army uniforms -- a method of attack already used several times this year by the Shebab.
"There were seven attackers. One of them blew himself up in the car while the six others were killed by the security forces," interior ministry spokesman Mohamed Yusuf told reporters.
"The attack is over now and the attackers have failed to achieve their goal aimed at interrupting the Indian Ocean operation," he said, referring to the current AU and government offensive.
Information Minister Mustafa Duhulow said three members of the security forces and two civilians were also killed, but that the attack was halted within 45 minutes.
The Shebab's military spokesman, Abdulaziz Abu Musab, confirmed the militants carried out the attack and claimed the militants had killed 15 government soldiers.
"Our courageous mujahedeen in Mogadishu succeeded in attacking the notorious Jila'ow prison, controlled by the apostate intelligence services. For a long time innocent Muslims suffered in the dungeons of that prison while being subjected to torture and humiliation," he said in a statement.
- AU-government offensive -
The Jilicow intelligence facility and detention facility is located close the Villa Somalia, the complex that houses the office of Somalia's internationally-backed President Hassan Sheikh Mohamud.
The Villa Somalia was hit by a similar attack in July, when a car bomb was detonated and Shebab fighters stormed the complex before blowing themselves up. The presidential palace was also attacked in a similar fashion in February, while the parliament complex was hit by a coordinated car bomb and gun attack in May.
Shebab rebels have continued to target key areas of government or the security forces, in an apparent bid to discredit claims by the authorities -- who are backed by the African Union's 22,000-strong AMISOM force -- that they are winning the war against the Islamist fighters.
On Saturday AMISOM said it had captured the town of Bulomarer, some 160 kilometres (100 miles) southwest of Mogadishu, as part of its "Operation Indian Ocean".
The town was the scene of an attempted raid by French commandos in January 2013 to free a secret agent being held hostage. The bid failed and resulted in the death of two French soldiers and the hostage.
AMISOM and Somali government troops were also seen on roads towards Barawe, the last major port held by the hardline gunmen on Somalia's Indian Ocean coast.
Deployed in Somalia in 2007, AMISOM has made a series of advances in the past three years. A new offensive launched on Saturday targets the Shebab's lucrative charcoal trade by cutting off access to the Indian Ocean coastline.
The southern port of Barawe is now one of the few major settlements under Shebab control, and is vital to Shebab finances -- with the export of charcoal generating at least $25 million (19 million euros) a year for the Shebab, according to UN estimates.