Fighting with M23 rebels in eastern Democratic Republic of Congo left six United Nations peacekeepers dead, UN officials said Saturday.

Thirteen soldiers serving with peacekeeping forces in the Democratic Republic of Congo have been killed in clashes with rebels from the M23 group. The South African military said nine of its soldiers died helping to push back a rebel advance on the city of Goma, in eastern DR Congo, while three Malawians and a Uruguayan were also killed.

GOMA, Congo (AP) — Nine United Nations peacekeepers in eastern Congo sustained injuries during fighting with the M23 armed group, the U.N. said, as the rebels close in on Goma. M23 has made significant territorial gains in recent weeks, encircling Goma, which has around 2 million people and is a regional hub for security and humanitarian efforts.