Police in Port Sudan said Monday it had imposed a night-time curfew in the Red Sea city after clashes broke out between members of two tribes in Sudan's main economic hub.
The curfew came into effect at 5:00 pm (1500 GMT) and would remain until 5:00 am Tuesday, the police said in a statement posted on its Facebook page.
It did not specify when the restrictions would be lifted.
Violence erupted on Monday in Port Sudan when a prominent leader from Beni Amer tribe held a political rally in the city which was opposed by members of Hadendowa tribe, the biggest in eastern Sudan, witnesses told AFP by telephone.
A bus was set on fire during the clashes that erupted near a hospital in the downtown area of Port Sudan, a witness said, adding there were people injured from both tribes.
"The clashes stopped after members of the Rapid Support Force intervened," another witness said.
"The situation is still tense and RSF members are everywhere."
Clashes erupted when members of Hadendowa tribe opposed the rally of Al-Amin Daoud, a prominent leader from Beni Amer tribe.
Tribal clashes have often rocked the northeast African country, with many resulting in deaths.
Port Sudan, the country's main economic hub, also witnesses regular strikes by port workers demanding better work conditions and pay.