Somali troops backed by African Union (AU) forces have retaken the al-Shabab stronghold of Barawe, key to the financing of the armed group.

Al Jazeera's Catherine Soi, embedded with the African Union Mission in Somalia (AMISOM) in Barawe, said: "Special forces are securing the city. They are having people open their doors, looking for al-Shabab elements."

Soi said that government officials and leaders of the AU force had held a meeting with locals on Monday, in a bid to gain their confidence.

"It has been years since the people of Barawe had seen any kind of government presence so there is still a lot of fear," said Soi.

Al-Shabab reportedly charged taxes to ships that sailed or docked at Barawe's port, raising revenues to expand its military campaign.

The AU said al-Shabab was using the town, which the al-Qaeda-linked fighters had held for six years, as a base to launch attacks on Mogadishu, the capital.

On Saturday, al-Shabab commander Mohamed Abu Abdallah vowed that the fighters would maintain pressure on Somali and AU forces even if they took Barawe.

Al-Shabab is fighting to topple Somalia's internationally-backed government, and regularly launches attacks against state targets, as well as in neighbouring countries that contribute to the AMISOM force.

The 22,000-strong force, with soldiers drawn from six nations, has been fighting alongside government troops against al-Shabab since 2007.