Mogadishu: Somalia’s Shebab insurgents were imposing Sharia law in the key port of Merka Saturday, residents said, one day after the Islamists retook their stronghold from African Union troops who had held it since 2012.

AU troops fled the city, the state capital of Lower Shabelle, as heavily armed Shehab fighters swept in with black Islamist flags on Friday, residents and local authorities said, in one of the most dramatic reverses for the multi-national force in its nearly decade-long battle against the Shebab.

‘The city is quiet and life is normal today, shops are reopening... but people who worked with the local administration are hiding in fear for their lives’, said one resident, Ibrahim Ahmed, reached by telephone from Mogadishu on Saturday.

‘Shebab fighters are patrolling in the streets and they asked people to avoid engaging in anything that could be a breach of the Sharia’, said another resident, Mohamed Mowlid.

The Al Qaeda-linked Shebab said on its website that one of its leaders, Sheikh Mohamed Abu-Abdallah, addressed hundreds of people gathered at the regional government headquarters in Merka on Friday.

‘The enemy has lost and running away, they are fleeing from the Islamic regions,’ it quoted him as saying.

‘The Islamic administration has started functioning officially in Merka and the fight among clans is over, there is no one who is superior to another, people are equal in front of God’s law’.

Vulnerable troops

The governor of the Lower Shabelle region, Ibrahim Adam, told reporters on Friday that ‘AU troops pulled out of the town and Shebab militants entered — and have secured control without fighting’.

The AU force, known by its acronym AMISOM, said on Twitter late Friday that its troops were ‘still in control’ of Merka but had been forced to ‘re-adjust their positions for tactical purposes.’ The statement sharply contradicted reports from residents and local authorities.

The historic port, some 100 kilometres (60 miles) south of the capital Mogadishu, was captured in August 2012 by African Union troops after four years under Islamist control.

It is one of the first major towns the Shebab have seized back and it gives them access to a sea port again.

The Shebab are fighting to overthrow the internationally-backed government in Mogadishu, which is protected by 22,000 AU troops.

The group has lost ground since being routed from Mogadishu in 2011, but continues to stage regular shooting and suicide attacks, and in recent months has staged a series of brazen raids on AU bases.

AU troops have been hampered by a lack of air power — including attack helicopters — leaving their bases often isolated and supply lines vulnerable to attack by Shehab gunmen controlling surrounding rural areas.