Soldiers are refusing to take on the rebels without pay
A UN base in eastern Democratic Republic of Congo has been fired on by army soldiers in a dispute over pay.
It is the latest in a string of mutinies in North Kivu by soldiers who have not been paid for six months.
A senior UN peacekeeper told the BBC that army commanders are not handing over soldiers' wages.
The army and UN forces are conducting an offensive in the region against ethnic Hutu rebels many of whom fled to DR Congo after the Rwandan genocide.
A UN spokesman told the BBC the situation needed to be dealt with urgently.
"There is a risk of a potential disintegration of the Congolese army," he said.
Over the last few months, members of the Tutsi-dominated rebel militia, the Congress for the Defence of the People (CNDP), have been integrated into the national army.
"There has been a fast-track integration of the CNDP and we are now seeing the results. The commanders are getting the money but not distributing it," the UN spokesperson said.
Shooting in the air
The BBC's Thomas Fessy in the region says 27 soldiers have been arrested after firing on the UN base about 100km (62 miles) north-west of Goma.
In another incident on Wednesday morning, soldiers in Ngora village (200km north-west of Goma) refused to pursue Hutu rebels from the Democratic Front for the Liberation of Rwanda (FDLR) into a neighbouring village.
They fired in the air for an hour-and-a-half, our correspondent says.
Two ringleaders were then arrested, which prompted more shooting.
Our reporter says there have been another nine such cases in the last week in North Kivu.
Villagers in the region are worried about their safety and soldiers have been stealing their crops to eat, he says.