Dozens of armed men stormed Bunia, the capital of DR Congo's northeastern Ituri province on Friday to demand the release of jailed militia fighters but they were peacefully evicted by security forces.
The heavily-armed men gathered in the city centre with rockets, AK-47 assault rifles and axes but were then bundled into three cars and driven out of the city, an AFP journalist said.
There was no exchange of fire.
The region's governor Jean Bamanisa told AFP earlier that the men had gathered outside the central prison to demand the release of their jailed peers.
"They are negotiating. We are trying to calm them," he said.
However some local sources said the men had come to give themselves up.
Several militia and rebel groups have been staging attacks in the region but this was the first time in recent years that they had entered a major city in the Great Lakes area bordering Uganda, Rwanda and Burundi.
Locals blamed the Cooperative for the Development of Congo (CODECO), an armed group accused of ethnic attacks and killing more than 1,000 civilians since December 2017, according to the United Nations.
CODECO is drawn from the Lendu ethnic group, a predominantly farming community which has historically clashed with the Hema, a group of traders and herders.
The two communities were embroiled in a bloody conflict between 1999-2003 which led to the European Union's first foreign military mission, the short-term Operation Artemis.
Governor Bamanisa said the men were from a CODECO faction which "unilaterally wants to end hostilities."
His deputy Gracien de Saint-Nicolas said: "We will not allow blood to be spilt in Bunia. The CODECO is Congolese and ready to give up arms but you are not facilitating the task for them to be reintegrated into the peace process."
UN human rights chief Michelle Bachelet visited Ituri in January and denounced what she called "crimes against humanity" there.