By Abdiqani Hassan and Abdi Sheikh

MOGADISHU (Reuters) - At least seven people were killed in weekend fighting between soldiers from two semi-autonomous regions of Somalia, officials from both sides said on Sunday, sparking fears of wider conflict.

The clashes which broke out on Saturday pitted forces from Puntland with those of Galmudug, the latest flare-up over a disputed area straddling their border.

The two sides are fighting in the town of Galkayo, which is divided between clan militias loyal to the different regions.

Hirsi Yusuf Barre, the mayor of Galkayo south, accused soldiers from Puntland of launching attacks first on Saturday.

"We lost three soldiers and 11 others were injured. We burned three vehicles belonging to Puntland," he told Reuters on Sunday.

Major Mohamed Ibrahim, a military officer in Puntland, said four soldiers were killed on their side and seven others were injured.

"We have repulsed them," he said.

Residents in the area said Galkayo was calm on Sunday but soldiers from both factions were seen reorganizing themselves for more clashes.

Earlier this month, the United Nations said the conflict could worsen and clashes had already displaced around 50,000 people.

Somalia has been at civil war for 25 years and clashes between the clan-based militias who control much of the country are common. In the south, forces loyal to the weak U.N.-backed government are also battling Islamist insurgents.

(Writing by Aaron Maasho Editing by Ruth Pitchford)