A new rebel group is threatening the key town of Bunia in the north-east of the Democratic Republic of Congo.
Firing on the outskirts of the town led to a stampede as local people left and shut shops hurriedly, according to the BBC's Thomas Fessy, in Kinshasa.
Bunia is the capital of Ituri province and an important base for United Nations peacekeepers.
It was also the scene of bloody fighting before a 2006 ceasefire led to a peace deal.
The new rebel coalition, the Popular Front for Justice in Congo - known by its French acronym, FPJC, had earlier taken a village close to Bunia, killing soldiers and sending thousands fleeing for their lives into the bush.
Mayhem broke out in Bunia on Friday after government troops clashed with the rebels less than 10km (6 miles) south of the town.
Local people, hearing the firing and fearful that fighting could erupt in the town centre, fled from the main market.
All the shops shut down and children were told to leave their schools and go home, our correspondent says.
New rebel coalition
United Nations troops reinforced their positions on the outskirts of the town and as night fell the situation calmed down and stability returned.
The area around Bunia suffered almost a decade of war, which ended with a peace deal in 2006.
But the rebels say they represent a new coalition, formed to force the implementation of that deal, which included an amnesty for all those who participated in the previous fighting.
Tension in the region has been growing over the past two weeks, with fighting between Congolese troops and the rebels moving closer to Bunia.