More than 10 people were killed on Saturday in fighting in Mogadishu between Islamic insurgents and troops of Somalia's beleaguered government, police and hospital sources said.
The fighting broke out in the northern district of Manbolyo when the rebels attacked a government position, police officer Abdulahi Dale told AFP.
"The fighting left more than 10 people dead so far but most of them are the combattants," he said. "Our forces are still in defensive positions and we have killed many terrorists.
The head of the Mogadishu ambulance service, Ali Muse, said, "We have seen around 11 people who died during the clashes this morning and the ambulances so far admitted 37 injured civilians in the hospitals."
The authorities could not confirm reports that a senior government military officer was among those killed.
Both sides claimed successes, with a spokesman for the government forces, Farhan Mohamed Arsanyo, showing journalists what he said was the body of an Afghan commander of the insurgents.
He was killed early Saturday in clashes in the northern Mogadishu district of Karan, Arsanyo said, adding, "We have nine others, some of them alive, and we will show (them) to the media."
Mohamed Osman, a commander from the rebel Hizb Al-Islamiya, replied, "What they are claiming is totally untrue, but I confirm that we have killed their officials this morning and including their commanders of the fighting."
Hizb Al-Islamiya and Shebab, a hardline Islamist armed group, launched an offensive against the internationally-backed administration of President Sharif Sheikh Ahmed on May 7.
More than 200,000 people have been displaced in the past two months, while hundreds of civilians are believed to have been killed and wounded, according to the UN Office of the High Commissioner for Human Rights.
A Shebab official Saturday denied a report that Islamist fighters had beheaded two men for supporting Ahmed's government.
"The information indicating that several people had been beheaded by Shebab is totally baseless and nobody has been executed", Sheik Mahad Omar, in charge of the central Bay and Bakol regions, told reporters.
Sources on Friday told AFP the men had been decapitated on Wednesday near Baidoa, a town in southern Somalia controlled by the militia.
The Shebab, fighting to oust Sharif, have imposed strict sharia, or Islamic law in areas under their control.
Last month Shebab militiamen chopped off the right hand and left foot of four people found guilty of theft by their court in Mogadishu.
UN High Commissioner for Human Rights Navi Pillay said in Geneva Friday that both sides were suspected to have committed war crimes.
"UN human rights staff have received credible reports that in areas controlled by insurgent groups, ad hoc tribunals are judging and sentencing civilians without due process and in violation of Somali as well as international law," her office said.
Punishments handed down by such tribunals include death sentences by stoning or decapitation, it added.