Dozens of soldiers and insurgents were killed in two days of fighting between Somali government forces and al Shabaab militants northwest of the capital Mogadishu, a witness told Reuters on Friday.

Somalia's state news agency Sonna said the military had killed about 50 fighters from the al Qaeda-allied Islamist group. No immediate account of the battle was available from the militants.

Hussein Ali, a farmer in the Afgoye area, told Reuters he and other civilians had been trapped in the crossfire during two nights of fighting.

"The Somali government transported dozens of dead bodies. Likewise, al Shabaab took dozens of their bodies. They both suffered blows," he said, adding he had counted at least 20 bodies on both sides.

Sonna, the state news agency, said that among the insurgents killed was a commander it identified as Osman il Fidow. "Al Shabaab buried its dead bodies in another village called Bulo Yarey," it said.

Neither the Somali military nor al Shabaab could be reached for comment. Both sides often give sharply different figures of fatalities in skirmishes.

Al Shabaab has been fighting for more than ten years to dislodge the country's central government and establish rule based on its strict interpretation of Islam's sharia law.

The group frequently carries out gun assaults and bombings of both military and civilian targets and has also carried out attacks on regional targets, especially in neighbouring Kenya.