Thousands of people took to the streets across the Democratic Republic of Congo to call for an end to violence in the east of the country, where government troops and United Nations peacekeepers are struggling to halt advancing rebels.

The protesters on Wednesday were angry over the four-month-old uprising by the M23 rebel group that has displaced some 470,000 civilians in the mineral-rich North Kivu province on the border with Uganda and Rwanda.

A UN experts' report found that senior officials in Rwanda were providing support to the Tutsi-dominated insurgency, and on Saturday Congolese President Joseph Kabila called Kigali's backing of the movement "an open secret".

Rwanda has repeatedly rejected the allegations and accused the report's authors of failing to verify their information or consult Rwandan authorities.

Early on Wednesday worshippers poured out of churches and into the streets brandishing banners calling for peace in the east and for unity in the vast country, which is home to nearly 70 million people and around 400 different ethnic groups.

"We're marching to say no to violence, to balkanisation and to the pillage of our resources," said Augustin, a young resident of the capital, Kinshasa, where the largest march was organised by Catholic Church leaders.

Smaller protest marches took place in cities across the country, including Lubumbashi in the southern mining heartland, and in Bukavu in South Kivu, which is also plagued by armed militias.

March 'allowed'

A planned march in Goma, the capital of North Kivu which has come within the rebels' striking distance in recent days, was called off for security reasons.

"Our country is being threatened by Rwanda and for the first time our government has understood this, that's why they've allowed us to march," Benoit Marcel Tshissambo, another Kinshasa protester, told the Reuters news agency.

Congo's government is regularly accused by human rights groups of using authoritarian methods to clamp down on dissent.

Congolese authorities repeatedly stopped the Catholic Church from organising pro-democracy marches in protest against Kabila's controversial re-election last November in polls widely denounced as fraudulent.

Congolese soldiers have been routed and pushed back in recent weeks in a replay of a 2008 rebel advance which saw the insurgents, then known as the CNDP, encircle Goma and clash with the army and UN soldiers on the outskirts of the city.

The front lines are now 30km from the provincial capital.

On Monday, the head of the UN peacekeeping mission in the country told the UN Security Council that Congolese troops had abandoned towns and villages to rebels and were suffering from a lack of ammunition, diplomatic sources told Reuters in New York.