Congolese rebels say they have repelled a dawn offensive by the army and a group of Rwandan Hutu fighters in the east of the Democratic Republic of Congo.

"The army and the Democratic Forces for the Liberation of Rwanda (FDLR) attacked the M23's position in Kibumba and Kanyamahoro. Our forces repelled the enemy," March 23 movement (M23) spokesman Vianney Kazarama said in a statement issued on Saturday.

However, the Armed Forces of the Democratic Republic of Congo (FARDC) denied that there had been any new fighting since the visit of UN Secretary General Ban Ki-moon, who toured the flashpoint city of Goma on Thursday.

"Maybe they were fighting among themselves or with other armed groups," FARDC spokesman for North Kivu province Olivier Hamuli said.

"Since the arrival of Ban Ki-moon, we haven't fought," he added.

"The army is not in Kibumba, it's a zone entirely under M23 control. We're staying on our side."

Several armed groups, including the M23 rebels, are active in the east of the DRC and fighting for control of the country’s vast mineral resources, such as gold, the main tin ore cassiterite, and coltan (columbite-tantalite), which is used to make many electronic devices, including cell phones.

The M23 rebels seized Goma on November 20 after UN peacekeepers gave up the battle for the frontier city of one million people. M23 fighters withdrew from the city on December 1 under a ceasefire accord.

The M23 rebels defected from the Congolese army in April 2012 in protest over alleged mistreatment in the FARDC. They had previously been integrated into the Congolese army under a peace deal signed in 2009.

Since early May 2012, nearly 3 million people have fled their homes in the eastern Congo. About 2.5 million have resettled in Congo, but more than 460,000 have crossed into neighboring Rwanda and Uganda.

Congo has faced numerous problems over the pas11t few decades, such as grinding poverty, crumbling infrastructure, and a war in the east of the country that has dragged on since 1998 and left over 5.5 million people dead.

In February, 11 African countries signed a UN-mediated peace agreement to end the crisis in the east of the DRC, which led to the establishment of a special brigade of UN peacekeepers with a mandate to attack rebel groups.

On Friday, the UN secretary general said in Kigali that Rwanda is the key to ensuring peace and stability in the east of the DRC.

Ban started a visit to the Great Lakes region of Africa on Thursday to promote the deal to end the long-running conflict in eastern Congo.