Chad's government announced Saturday it was closing its border with Sudan after battles erupted between rival military factions in the neighbouring country.

Sudan's army carried out airstrikes against the bases of a paramilitary force, as weeks of tensions between two military commanders erupted into violence.

"Faced with this troubling situation, Chad, while securing its borders, has decided to close the frontier with Sudan until further notice," government spokesman Aziz Mahamat Saleh said in a statement.

Chad shares a more then 1,000 kilometre (600 mile) border with Sudan, much of it abutting Darfur, long the theatre of tribal violence, often fueled by disputes over territory and water.

"The fighting is not only in Khartoum" and there is "a risk of spillover and infiltrations," a member of the Chadian government told AFP on condition of anonymity.

In Sudan, military leader Abdel Fattah al-Burhan and his deputy, paramilitary commander Mohamed Hamdan Daglo, have been at loggerheads over the planned integration of Daglo's paramilitary Rapid Support Forces (RSF) into the regular army.

The integration was a key element of talks to finalise a deal that would return the country to civilian rule and end the political and economic crisis sparked by their 2021 coup in one of the world's poorest countries.

Three civilians have been killed in the violence and both the paramilitary force and the army are claiming control of key locations, while calls mount from foreign allies for an immediate ceasefire.