Credible reports of Congo's defeated M23 rebels regrouping: U.N. By Michelle Nichols UNITED NATIONS (Reuters) - Congolese rebel group M23 appears to be regrouping just two months after the Tutsi-led insurgency was defeated by Congolese troops and U.N. peacekeepers, the top U.N. official in the Democratic Republic of Congo said on Monday. Martin Kobler told the U.N. Security Council there were "credible reports of emerging M23 activities in Ituri in northeastern Congo" and called on the Congolese government to speed up the disarmament, demobilization and reintegration of ex-M23 fighters, who ended their 20-month revolt in November. At the same time, I call upon the governments of Uganda and Rwanda to do everything possible to prevent M23 elements from sheltering or training troops on their territory. We should tolerate no military re-emergence of the M23," he said. Kobler told reporters after briefing the council that "there might be a danger of renewed military infiltration of the country" by M23. U.N. experts - who monitor violations of U.N. sanctions on Congo - have long accused neighboring Rwanda and Uganda of backing M23, claims that both governments have rejected. In a report to the Security Council's Congo sanctions committee in December, the experts said they had credible information that blacklisted M23 leaders were moving freely in Uganda and the group was still recruiting fighters in Rwanda. M23 is one of dozens of rebel groups in eastern Congo. Millions of people have died from violence, disease and hunger since the 1990s as armed groups fought for control of the area's deposits of gold, diamonds, copper, cobalt and uranium. Mary Robinson, the U.N. special envoy to the Great Lakes who is charged with implementing a regional peace deal, told the 15-member Security Council that Congo and neighboring countries needed to take some confidence-building steps. These steps included showing "none is harboring individuals responsible for grave human rights violations, none is giving any kind of support or assistance to armed groups, none is interfering in the affairs of a neighboring country." "There is worrying evidence that these commitments are not yet being fully implemented by Rwanda and Uganda," she said. Rwanda's deputy U.N. ambassador, Olivier Nduhungirehe, said there was no evidence that Rwanda supported M23. He said that Rwanda had interned more than 600 M23 fighters who had fled across its border in March last year and that Kigali had repeatedly asked the United Nations to take charge of them. Uganda's U.N. mission in New York did not immediately respond to a request for comment. Rwanda has repeatedly intervened in Congo, saying it had to hunt down the Hutu militia who fled after the Rwandan genocide. Rwanda and Congo have fought two wars in the past two decades in eastern Congo. Rwanda has accused Congolese troops of collaborating with the Democratic Forces for the Liberation of Rwanda (FDLR), which includes Hutus who fled Rwanda after the 1994 genocide of 800,000 Tutsi and moderate Hutus. Kinshasa denies the claim. Kobler told the Security Council that since the defeat of M23, Congolese troops and U.N. peacekeepers had turned their attention to tackling the FDLR. He said first operations against the group had cleared some positions. Operations can only be successful if done jointly with the Congolese Army. I do encourage the Congolese Forces to do more and to intensify the joint planning and execution of operations against the FDLR," Kobler said. He also said military action could be expected soon against the Islamist Allied Democratic Forces (ADF), a group that "continues to spread terror and horror" in the Ituri region of Congo's northeastern Orientale province. Kobler cited to the Security Council an example of the ADF's brutality toward civilians. "On 13 December, in an ADF-controlled area, 21 bodies, including the bodies of eight babies, very young children and pregnant women, were found dead, mutilated and some beheaded," he said. Three of the children were reportedly raped before being murdered. Kobler said that in 2013, 151 children were killed or maimed, including babies caught in cross-fire and primary school students who were summarily executed. The U.N. mission found that 260 underaged girls were raped by rebels and government troops. The 20,000-strong U.N. peacekeeping force in Congo received a boost last year with the unprecedented deployments of unarmed surveillance drones and an Intervention Brigade of 3,000 troops to help Congolese forces hunt down rebel groups. The presence of armed groups is still strong, too strong. We need to keep the momentum," Kobler said. With the Force Intervention Brigade and our Unmanned Aerial Vehicles, all armed groups are aware now that we have the will and the means to take robust action at any time. Reporting by Michelle Nichols; Editing by Richard Chang