Fighting in Sudan spread to the coastal city of Port Sudan on Monday for the first time since war broke out more than five months ago.
Witnesses told AFP that the Sudanese army clashed with tribal militiamen loyal to Sheba Darar, a leader from the Beja tribe, in the city centre.
One said “soldiers deployed in the area after removing checkpoints set up by the militia”, while others reported a “return to calm” soon after.
Thousands have been killed in Sudan after clashes broke out in April between forces loyal to army chief Gen Abdel Fattah Al Burhan and his former deputy Gen Mohamed Dagalo, who commands the paramilitary Rapid Support Forces.
Most of the fighting has taken place in the capital Khartoum and the western Darfur region, while Port Sudan and the east have been relatively quiet.
Most tribes in eastern Sudan have pledged support to the army.
Mr Darar, whose militia was reported to have clashed with the army on Monday, supported the army at the start of the war and is not allied with the RSF.
However, he was reported to have been angered by government officials after Gen Al Burhan moved his base to Port Sudan last month.
The city is home to the country's only functioning airport and hosts government officials and the UN.
Gen Al Burhan, who spent the first months of the war trapped in army headquarters in Khartoum, arrived in Uganda on Saturday in the latest of several trips abroad seen as an attempt to strengthen his status at Sudan's legitimate leader.
Gen Al Burhan met Turkish President Recep Tayyip Erdogan in Ankara last week and has recently visited Egypt, Eritrea, South Sudan and Qatar.
He is also expected to attend the UN General Assembly in New York.
Battle for Khartoum rages
The army and the RSF continued to fight for control of Khartoum on Monday, according to witnesses who reported heavy artillery and air strikes in the city.
For the third day in a row, the RSF attacked army headquarters in central Khartoum, while the army responded with air strikes and drones.
Others in Omdurman, across the Nile, reported the army attacking RSF bases with artillery.
Both forces have been accused by human rights campaigners, aid groups and international organisations of attacking infrastructure and failing to protect civilians.
The UN's human rights chief recently condemned the RSF and its allies for committing “ethnically motivated” attacks in the West Darfur region, saying the war has “broken the nation.”
The war has damaged already fragile infrastructure, forced the closure of 80 per cent of the country's hospitals and forced millions of people into acute hunger.
Doctors in the city of Omdurman, where five hospitals remain operational, have told The National many patients have died following critical shortages of medicine and basic supplies.
The war has also doubled the number of internally displaced people in Sudan to more than seven million, according to the UN.