Tensions between Somalia's self-declared republic of Somaliland and the autonomous region of Puntland have risen, prompting some aid workers to temporarily leave the area, an NGO said.

The German Agro Action organisation has temporarily withdrawn its staff from Burao, Erigavo and Borona, where clashes between militias and troops from the two territories have claimed 10 lives over the past few days.

"The conflict has been building up for a long time; but outbreaks of fighting have now become extremely serious," said Peter Sass, head of the NGO's office in Burao, the capital of Puntland.

The clashes were partly caused by a dispute over water in Los Anod town, Sool region, said German Agro Action. Both territories claim the town, although it has been held by Puntland forces since December 2003.

On 17 September, forces from the two territories clashed in Abeseoley near Los Anod, forcing scores of families to flee their homes.

Ahmed Aden Arab, the Puntland deputy minister for local government, blamed Somaliland forces for starting the shelling but Somaliland spokesman Said Adani dismissed the accusation.

Sool and Sanag regions fall within the borders of pre-independence British Somaliland, but most of the area's inhabitants, the Warsangeli and Dhulbahante communities, who are members of the larger Darod clan, are associated with residents of Puntland.

"The risk of continuing our work under these conditions is simply too high," Sass said. "We hope to be able to restart our work soon."