Fighter jets bombed the southern Somali town of Baardheere on Thursday, killing at least one civilian, and fighting broke out in the north of Mogadishu, exposing the government's struggle to secure the capital.

Some locals believed the warplanes came from neighbouring Kenya, which is eight weeks into an offensive in Somalia aimed at crushing rebel networks, and has carried out air strikes.

Two fighter jets bombed the ADC stores in a suburb of the town, resident Ali Mohamud Ali told Reuters by telephone. Residents said the rebels had been using the retailer's large compound as a training base.

Kenya's military spokesman was not available for comment.

Sheikh Abdiasis Abu Musab, a spokesman for al Shabaab fighters, said the aircraft dropped two bombs, killing an elderly man and wounding his daughter in a house nearby.

There were no rebel combatants at the site at the time, he said. Residents were unable to verify the statement.

Kenya's presidential press service reported that U.N. chief Ban Ki-moon fully understood why Nairobi had sent forces across the border on a visit to the east African country.

He lauded the decision taken by the cabinet and approved by the Kenyan Parliament to re-hat Kenyan forces in Somalia under the AMISOM command, State House said in a statement.

Kenya wants its troops to be a part of the African Union (AU) peacekeeping force, known as AMISOM. The AU and regional IGAD block back Kenya.

If Kenya wants AMISOM to help fund its operation on the ground as part of the African Union force, the U.N. Security Council would need to approve extra funding, analysts said.

FIGHTING ROCKS MOGADISHU

The al Qaeda-linked rebels have waged a five-year insurgency to topple a government plagued by internal feuds and corruption. Their campaign has killed tens of thousands of civilians and centred on the capital, Mogadishu.

Fighting erupted in the northern outskirts of the coastal city early on Thursday after al Shabaab attacked government troop positions in the Daynile, Karan and Huriwa neighbourhoods.

Al Shabaab withdrew most of its fighters from Mogadishu in August, weakened by divisions within its ranks, but retains control in a few small pockets of the city. Since then the rebels have launched frequent assaults on these areas.

Al Shabaab launched the attacks against our defence positions in Huriwa, Daynile and Karan districts. We resisted them, Burhan Ali Yusuf, a government soldier stationed on the frontline, told Reuters.

Thursday's clashes are a blow to a government desperate to convince the population and foreign powers it can improve security in the city and beyond.

Al Shabaab announced details of the air strike and fighting on the social media site Twitter, a day after launching its official Twitter feed which has attracted hundreds of followers. The rebels confirmed the site was authentic by email.

Some observers believe the account was set up to counter the prolific tweeting of Kenya's military spokesman, Emmanuel Chirchir, who routinely provides details of the army's military operation on the micro-blogging site.

(Additional reporting by Sahra Abdi and Richard Lough in Nairobi; Writing by Richard Lough Editing by Maria Golovnina)