The head of the UN peacekeeping mission in Democratic Republic of Congo said its staff and vehicles were attacked in the capital Kinshasa on Saturday as a worsening eastern security crisis fuels a backlash against the mission.

Crowds on motorbikes gathered in the riverside Gombe district, where the UN mission known as MONUSCO and many embassies are located. They burned tyres and attacked people, a Reuters reporter said.

A number of the mission’s vehicles were torched, said MONUSCO head Bintou Keita in an online post.

"I strongly condemn the series of attacks," she said

The Ivorian embassy also said one of its vehicles had been vandalised in Kinshasa, and described indiscriminate attacks on vehicles belonging to embassies and international organisations.

Kinshasa police and the government did not respond to a request for comment.

An advance by rebel group M23 that threatens the strategic eastern city of Goma in conflict-torn North Kivu province has aggravated a decades-old security and humanitarian crisis.

Clashes between the rebels, the armed forces and self-defence groups that support the army have escalated in recent weeks, forcing over 135,000 more people to flee to perceived areas of greater safety near Goma, the UN humanitarian agency OCHA said on Thursday.

The fighting "could compromise food security and economic activities in Goma and the region. The risk of Goma being isolated is high," it said.

MONUSCO has been deployed in eastern Congo since taking over from a previous UN operation in 2010. Its mandate includes supporting the Congolese government’s effort to stabilise the region, but in recent years it has faced sometimes violent protests linked to perceptions it has not done enough to stem the eastern bloodshed.