(Reuters) -Nine South African soldiers have been killed in eastern Congo's conflict zone, the South African defence department said on Saturday, as Congolese troops and peacekeepers battled to stop an advance by Rwanda-backed rebels on the city of Goma.

The casualties occurred Thursday when M23 rebels attacked Sake in the eastern DRC, said the DA, which is part of South Africa’s governing coalition.

Nine South African soldiers have died in eastern Congo during intense fighting against Rwanda-backed rebels. The escalating conflict, marked by the M23 insurgency, has displaced 400,000 people, prompting UN concerns about regional stability.