Chad closed its eastern border with Sudan on Monday after weekend clashes linked to Sudan's civil war killed five Chadian soldiers, two sources told Reuters.

The conflict in Sudan between the Sudanese army and the paramilitary Rapid Support Forces, which erupted in April 2023, has periodically spilled over into Chadian territory, causing casualties and property damage.

A Chadian official told Reuters that clashes on Saturday between the RSF and militia fighters loyal to Sudan's government in the border town of Tine killed five soldiers and three civilians and wounded 12 people.  

A border guard officer in Tine confirmed the deaths of the five soldiers and said additional security measures were needed to protect civilians on the Chadian side.

The two sources, who spoke on condition of anonymity because they were not authorised to speak to the media, said more Chadian troops were being deployed to the area. 

Chad's government said on Monday that the border would remain closed until further notice, citing "repeated incursions and violations committed by forces in Sudan's conflict."

The move "aims to prevent any risk of the conflict spreading to our soil, to protect our fellow citizens and refugee populations, and to guarantee the stability and territorial integrity of our country," a government statement said.

Sudan's army and the RSF did not immediately respond to requests for comment.

Last year, a drone attack killed two Chadian soldiers, according to local authorities and a security source, though it was unclear who carried out the attack.

"One thing is certain: whether we like it or not, Chad now appears to be a party to the conflict," said Ahmat Yacoub from the Center for Studies for the Development and Prevention of Extremism, a think tank.