Safari Hangi walked for hours with a baby strapped to his back and six young children in tow trying to find safety as apparent gains by rebel forces in eastern Congo sparked a fresh exodus of people towards the provincial capital Goma.

The family was among hundreds of Congolese fleeing on Friday through the town of Sake, which they no longer saw as secure after the M23 rebel group appeared to gain control of the frontline hotspot of Mushaki around 15 km (9 miles) to the west.

"If it weren't for this war, we would be in our village without any problems, farming and getting on with daily chores," said Hangi, 42, as the family paused to rest on the stony road.

"Now that we are displaced, that's all over and we suffer," he said, worrying out loud about how his young son would manage the long distance ahead with no shoes.

Congo's army did not immediately reply to a request for comment on the security situation, but a senior army official said Congolese troops had chosen to draw back from Mushaki and withdraw their artillery from Sake to avoid civilian casualties.

"The M23 did not take Mushaki. There was a strategic withdrawal," the official said, speaking on condition of anonymity. "There are many displaced people in Sake and the fighting was coming closer."

The Tutsi-led M23 staged a comeback last year after being chased into neighbouring Rwanda and Uganda in 2013. Since the new offensive, the group has seized swathes of North Kivu province and displaced hundreds of thousands of people. The government accuses it of mass atrocities and flouting a ceasefire deal.

M23 spokesman Lawrence Kanyaka told Reuters the only threat to civilians was from Congolese forces' use of heavy weapons and their alliance with other armed groups. Congo denies cooperating with other militant groups active in the area.

A large number of Congolese troops guarded a checkpoint on the edge of Sake on Friday, monitoring those going in and out of the town. The situation appeared calm, but the streets were more empty than usual, the normally bustling marketplace was quiet, and its stalls were bare.

The town is one of the last remaining trade links for Goma, 15 km to the east. The city has seen prices for everyday goods soar after rebels seized key agricultural areas and severed supply routes.

Market trader Pascal Habamungu Kasilika said the rebel advance to Mushaki had made for an uneasy night.

"It worries us. We ask ourselves - where do we go? Where do we flee to? Who do we go to for help? This problem is beyond us."