MOGADISHU, Oct. 2 (Xinhua) -- A blast hit the regional administration office in the southern town of Kismayo of Somalia after Somali government forces entered the city following the withdrawal of militant Al-Shabaab fighters at the weekend, military commander and residents said.
"It was a bomb that was planted in the administration office. It went off but it did not harm anyone. We have arrested a man suspected of remotely detonating the device," Ismail Sahardeed, commander of Somali government forces in Kismayo, told Xinhua by phone
The explosion partly destroyed the local administration building after the bomb went off, residents said.
The explosion, claimed by the militant Al-Shabaab group, came one day after Somali government forces and African Union peacekeeping troops entered the strategic port city.
The group, in a twitter post, said they were casualties in the blast. "Huge explosion targets apostate militia attempting to enter the regional admin office, K2 building, in Kismayo leaving scores dead and injured," Al-Shabaab tweeted.
Fighters from the radical rebel group of Al-Shabaab on Saturday left the strategic port city of Kismayo following months of offensive by Somali government troops backed by Kenya forces who are part of the African Union peacekeeping mission in Somalia (AMISOM).
Kismayo, the largest port city under Al-Shabaab group, is 500 km south of the Somali capital Mogadishu, and has been a key revenue earner for the al-Qaida-affiliated in Somalia.
The militants levied heavy tariffs on the main charcoal exports and other imports via the port, the largest in the southern Somalia.
The fall of Kismayo will deal a huge blow on the radical militants of Al-Shabaab who have lately been suffering from a string of losses of important areas in Somalia.