Local media reported hundreds of armed men were seen leaving the city on flat-bed trucks, 11 days after the city was taken over by anti-government forces, the BBC said.
United Nations peacekeeping troops didn't report any armed engagements, although several vehicles transporting goods deemed to be rebel-related were stopped.
The rebels, largely military deserters who have named themselves M23, were moving outside a 12-mile U.N.-declared safe zone from Goma, the BBC and CNN said.
Both neighboring Uganda and Rwanda have denied various international accusations they are supporting DR Congo rebels.
U.N. agencies say at least 5 million people have died in the rebellion that began in 1997.
Notable deaths of 2014 [PHOTOS]
U.N. opens climate summit