Chad closed its eastern border with Sudan "until further notice" on Monday saying the move was needed to stop repeated incursions by Sudanese armed groups.

A government spokesperson said the decision aimed to protect citizens but added that "exceptional exemptions, strictly justified by humanitarian reasons", may be granted with prior authorisation from the relevant authorities.

The closure was announced after heavy fighting erupted in the border town of al?Tina between Sudan's Rapid Support Forces (RSF) and local fighters aligned to the Sudanese army.

Almost a million Sudanese have crossed the border into Chad since the civil war broke out in 2023.

Chad is also an important entry point for humanitarian workers and convoys heading to its war-ravaged neighbour.

Chadian authorities said the border closure was introduced as a security precaution after the war in Sudan drew closer to Chadian territory, amid reports that Sudanese militants had crossed into Chad.

In a statement, Chad's Communications Minister Mahamat Gassim Cherif said the move was intended to prevent the conflict from spreading and to safeguard citizens and refugee communities.

Sudan has been locked in a violent power struggle since April 2023, when a dispute between the national army, led by Gen Abdel Fattah al?Burhan, and the RSF, commanded by his former deputy Gen Mohamed Hamdan Dagalo, commonly known as Hemedti, escalated.

A disagreement over merging the RSF into the regular army quickly grew into a full?scale war.

Chad further warned that the government ''reserves the right to retaliate against any aggression or violation',' urging residents of affected areas to remain calm, stay alert and comply with the new restrictions.

Fighting broke out over the weekend in the border town of al-Tina, where Chadian troops were caught up in violence involving Sudanese armed groups.

Officials told the Reuters news agency that five soldiers and three civilians were killed, and at least 12 others wounded.

Sudan's army has additionally accused Chad of supporting the RSF and allowing military supplies to transit through its territory - allegations the Chadian government has previously denied.