Two loud explosions rocked a rebel stronghold about 13 km from the Somali capital on Saturday and a third blast was heard close by, residents said, but it was unclear who Was behind them.

We heard two big explosions and then we saw clouds of smoke rising from near the bases of al Shabaab near the Al Hayaat hospital, Keise Osman, a resident of Elasha, told Reuters.

Another resident from Lafole, close to Elasha, said she heard the first two blasts and then a third explosion nearby.

We are in shock. We do not know if they are shells from the African Union (AU) forces or missiles from a warplane, Shukri Farah said from Lafole.

The al Qaeda-linked insurgents said artillery fired by the AU's AMISOM peacekeepers had struck Elasha town, hitting a civilian car and narrowly missing the hospital.

An AMISOM spokesman said there had been no shelling on Saturday by its troops.

Al Shabaab are also battling a military offensive by Kenya, which has carried out frequent air strikes on militant bases. If this was a Kenyan bombardment it would be the closest site to the coastal capital their shelling has come in the three-month-old campaign.

Kenya's military spokesman was not immediately available for comment.

(Reporting by Abdi Sheikh and Feisal Omar; Writing; by Richard Lough; editing by Tim Pearce)