On Wednesday, AFP correspondents saw tighter security in the towns of Beni and Butembo, as well as in Goma, the provincial capital.

Armed police and soldiers were patrolling Beni in jeeps and a highway leading out of the town towards several MONUSCO bases was heavily guarded.

Relative calm had also returned to Goma, where shops were beginning to open again as security forces deployed across the city.

In the town of Sake about 30 kilometres (18 miles) from Goma, Congolese police fired tear gas to disperse protesters near a UN base, which was ringed with soldiers and police officers.

"We will protest until they leave," said Jackson Kibuya, a protester in Sake, holding up a banner reading "Bye Bye MONUSCO".

More than 120 armed groups roam the volatile region, where civilian massacres are common and conflict has displaced millions of people.

Crowds stormed a UN peacekeeping base and a supply centre in the city of Goma in North Kivu province on Monday, looting valuables and chanting hostile slogans.

Protests quickly spread and on Tuesday, three UN peacekeepers were killed in an attack on their base in the town of Butembo.

Twelve protesters have died, in addition to the peacekeepers, according to a government toll.

The UN mission in the DRC, known as MONUSCO, is one of the world's biggest peacekeeping operations.

But it has come under regular criticism in Congo's troubled east, where many accuse it of failing to do enough to end decades-old attacks by armed groups.