A Kenyan contingent of about 300 soldiers was the first to leave their positions in Goma, the capital of North Kivu province, early on Sunday.
The troops were deployed in the region about a year ago at the request of DR Congo’s government in the hope of containing the resurgent M23 rebel group.
But the government has since criticised the East African force as ineffective and has refused to renew its mandate.
Kenya troops occupied Kibumba and Kibati and other positions north of Goma.
In a statement, the M23 said it “will recover and occupy all areas” that it handed over to the regional forces at the beginning of the peace process.
A ceasefire agreed to last month has been ignored, leading to fresh fighting.
DR Congo’s President Félix Tshisekedi, who is seeking reelection, has said rebel-controlled territories might not participate in the December vote for security reasons.
It is not clear when soldiers from other countries will start to leave their positions.
Late last year, M23 rebels handed areas they had captured in the Rutshuru, Masisi and Nyiragongo areas of North Kivu to contingents from Burundi, Kenya, South Sudan, and Uganda.
This was in line with a peace deal reached in talks in Kenya and Angola.
Source: bbc.com
