At least 30 people have died and more than 100 were injured in intensified fighting between the Somali National Army and its former ally Ahlu Sunnah Wal Jama'a in the Somali state of Galmudug over the weekend, residents and hospital officials say.
The clashes, in the state's second-largest district of Guriceel, run the risk of distracting both groups from their fights against al-Shabab, analysts and residents said.
This round of fighting broke out early on Saturday and continued into Sunday, residents said.
"I am sure over 30 people died because I know 27 of them and they belong to both groups," elder Farah Abdullahi told Reuters.
His estimates were echoed by 10 residents interviewed individually by Reuters.
Both the army and ASWJ were not reachable for comment.
ASWJ is a group of moderate Sufi Muslims which has played a key role in the fight against the al-Shabab insurgency.
But tensions between the armed group and the federal government have been building for years.
ASWJ accuses the government of not doing enough to fight al-Shabab while the government accuses ASWJ of acting without its permission.
Tensions came to a head earlier this month when federal forces launched what it called a pre-emptive attack on ASWJ.
ASWJ repelled the attack and captured Guriceel, whose residents welcomed the group.
The dead from the weekend's fighting include senior SNA officer Abdi Ladiif Fayfle, the commander of the US-trained Danab forces, a relative told Reuters.
Fayo Care Hospital in the town received 30 people injured in fighting while Istarlin Hospital, also in the town, said it received 10, officials at the hospitals said.
Hanano Hospital in a nearby town received 60, an official said.
The SNA also airlifted a plane of injured soldiers to the capital, an airport worker told Reuters.
Galmudug state security minister Ahmed Moalim Fiqi resigned earlier this month, citing federal officials' refusal to heed his pleas not to attack ASWJ.
"Many parts of Galmudug and the entire country is under al-Shabab. The commander of SNA is destroying Guriceel town and massacring ASWJ who are famous for eliminating al-Shabab," he said on Saturday.
Later on Saturday, al-Shabab militants hit a Galmudug airport with mortars, airport workers said, compounding fears that the group would take advantage of the chaotic infighting.
"The escalation of the dispute between ASWJ and the government distracts from, if not undermines, other priorities like progressing with elections and the struggle against al-Shabab," said Omar Mahmood, Somalia analyst at the International Crisis Group thinktank.
Australian Associated Press