Conflict between M23 rebels and government forces is intensifying in eastern Democratic Republic of Congo's Masisi territory, local sources said, with six killed on Wednesday and many more injured.
Tensions in Masisi have displaced residents of many villages and overwhelmed health centres, according to humanitarian sources.
Residents pointed to the town of Sake, a strategic point on the road to the city of Goma, as a flashpoint in the latest fighting in the eastern North Kivu province.
According to medical and security sources, at least six people were killed in Wednesday's bombardments in Sake.
Throughout the day, thousands of people fleeing the fighting arrived in the provincial capital Goma, around 20 kilometres (12 miles) away, they said.
"We woke up this morning to the sound of bangs and explosions," Patrick Manga, a 35-year-old father of four, told AFP as he left carrying two mattresses on his head.
"We realised that we were all going to die and decided to flee."
Florence, a mother of nine who fled Sake, said she had lost some of her children in the chaos.
"Other children may have died, please tell (President Felix) Tshisekedi to bring us peace," she cried.
An administrative official reported that the fighting was intensifying in the hills around Sake.
Later in the day, one resident said: "We are hearing explosions, but not on the same scale as what we have been experiencing all day... We don't know if the lull will last."
After years of dormancy, the M23 (March 23 Movement) took up arms again in late 2021 and has since seized vast swathes of North Kivu.
The province's territories of Rutshuru and Masisi have borne the brunt of the fighting between Congolese armed forces and the M23, which Kinshasa says is supported by neighbouring Rwanda.
The UN backs the claim of Rwandan involvement, which Kigali denies.
After a lull during the December 20 election which returned Tshisekedi for a second term, fighting has resumed around Goma.
Army spokesman General Sylvain Ekenge told reporters late Tuesday there had been "intense fighting" for control of a stretch of highway running between Sake and Minova, a small town in the neighbouring province of South Kivu.
A medical source in Sake said the local health centre had received around 20 wounded people, "mostly civilians" and some of them seriously hurt, in the past three days, while another in Minova reported about 30 such cases.
The unrest has cut off most supply routes to Goma, a city of more than one million people near the Rwandan border which the rebels seized more than a decade ago before being driven out.
Concerned at the risk of a "regional explosion", the UN Under-Secretary-General for peacekeeping operations, Jean-Pierre Lacroix, on his return from a visit to the east of DR Congo, called in Kinshasa for an urgent resumption of "diplomatic efforts" to resolve the conflict.
Kinshasa has called for the "accelerated" departure of the UN mission in the country, MONUSCO, on the grounds that they are ineffective.