At least 47 people have been killed and 100 injured in fighting in the central Somali town of Dhuusa Marreeb, a human rights official has told the BBC.
Ali Yasin Gedi, of Somali human rights group Elman, said many people had fled the town where allies of the government fought to drive out Islamist rebels.
The pro-government Ahlu Sunna group is said to have recaptured the strategic town from al-Shabab militants.
The militants were reportedly in control of the town for a few hours.
Correspondents say Ahlu Sunna was founded as a non-violent group to promote moderate Sufi Islam but decided last year to take up arms against the radical al-Shabab group, which is accused of links to al-Qaeda.
Somalia has not had a functioning national administration since 1991. Its UN-backed government controls only a few parts of the capital, Mogadishu.
Mr Gedi said his information was based on conversations with his organisation's workers in the town, 500km (310 miles) north of the capital, Mogadishu.
He told the BBC that some people had been taking the wounded to hospitals elsewhere in the region.
"Our monitoring office has confirmed that most of the casualties were from the warring factions, but some civilians were also killed," he said.
"Many people who fled from the town have not returned yet and they are in the outskirts of the town without shelter and the sun is extremely hot."
One resident, Hussein Moalim Mahad, told AFP news agency the fighting had been "the most violent ever seen in Dhuusa Marreeb".
Local chief Abdulahi Gedi said he had sent out two teams to collect bodies lying inside and outside the town.
Unverified reports say al-Shabab has been spotted regrouping in areas outside the town.
It is said to be the first fighting in the area since Ahlu Sunnah defeated al-Shabab a year ago.