The armies of breakaway Somaliland and Puntland early Thursday engaged each other in heavy fighting, reports said.
Both sides reportedly employed light and heavy guns near Tukaraq District, about 1,100km northwest of the Somali capital Mogadishu.
The casualty figure were not immediately available.
Somaliland and Puntland have hand long-standing border disputes, particularly over Sool and Sanaag regions that separate them.
Somaliland controls most of the disputed territories.
Troops of the breakaway state seized Tukaraq town from Puntland in January this year, and the two sides have since then engaged in intermittent gun fights.
Somaliland in the northwest declared independence from the rest of Somalia in 1991, but has since failed to win international recognition.
Puntland was established as a semiautonomous authority in 1998, but remains a member state of the Mogadishu-based federal government of Somalia.