At least 45 soldiers touched down in the city of Goma in the late morning, with further contingents expected to arrive at later dates.

The South Sudanese soldiers are part of the seven-nation East African Community (EAC) military force, which was created last June to stabilise eastern DRC.

Much of the region is plagued by dozens of armed groups, a legacy of regional wars that flared in the 1990s and 2000s.

Since re-emerging from dormancy in late 2021, M23 rebels have also captured swathes of territory in North Kivu province and advanced within several dozen kilometres of its capital Goma.

The EAC force -- which comprises Kenyan, Burundian and Ugandan troops as well as South Sudanese -- is due to supervise a planned pull-back of the rebels.

"Welcome to Goma," said Colonel Jok Akech, an EAC force officer, addressing the new South Sudanese arrivals.

"Now you are in a different operational environment. You have to be ready."

The M23 first came to international prominence in 2012 when it captured Goma, before being driven out and going to ground.

But the Tutsi-led group re-emerged from dormancy in late 2021, arguing that the government had ignored a promise to integrate its fighters into the army.

It then won a string of victories against the Congolese army and captured large chunks of North Kivu, with hundreds of thousands of people fleeing its advance.

Several regional initiatives intended to defuse the conflict have failed.

A ceasefire mediated by Angola was due to take effect on March 7, for example, but collapsed almost immediately.

March 30 was supposed to mark the end of the withdrawal of "all armed groups", according to a timetable adopted in mid-February by the EAC.

The deadline was not respected.

The EAC force commander, Kenyan General Jeff Nyagah, told reporters on Friday that the planned M23 withdrawal would be "sequenced".

The DRC accuses its smaller neighbour Rwanda of backing the M23, something the United States, several other Western countries and independent UN experts agree with, but which Kigali denies.