By Will Ross
BBC News, Kampala
The United Nations mission in the Democratic Republic of Congo says it is concerned by the creation of a new rebel group in neighbouring Uganda.
The UN is trying to disarm rebel groups in the east of DR Congo
Uganda may be violating its international obligations by allowing its territory to be used by armed groups from eastern DR Congo, it says.
Uganda's army confirmed Congolese rebels had been in Uganda but denied officials had been working with them.
The new group's founders are wanted by a prosecutor in eastern DR Congo.
The BBC has seen a document announcing the formation of the Congolese Revolutionary Movement (MRC), which says it is fighting for the rights of the people in DR Congo's eastern Ituri and North Kivu regions.
The group is made up of elements of various groups operating in the east.
The document announcing the formation of the MRC, which describes itself as a political and military movement, was signed by 15 men - all of whom are now wanted by the chief prosecutor in the Congolese town of Bunia.
It indicates that it was signed last month in Uganda's capital, Kampala.
Ugandan army spokesman Lieutenant Colonel Shaban Bantariza said Congolese rebels had been in Uganda recently - but he said they had been visiting on personal business.
He denied that officials of the Ugandan government had been working with them and said they had requested that Ugandan government put pressure on Kinshasa to integrate the men in the national army.
Last month Uganda's President Yoweri Museveni wrote to his Congolese counterpart Joseph Kabila, complaining about the lack of disarmament of militia fighters in the east.
Justin Lobho of the MRC is wanted by the chief prosecutor in Bunia
He warned that Uganda would "react vigorously" if attacked.
Despite the official statements of denial by the government, Uganda is likely to once again come under suspicion of working with Congolese rebels.
The UN mission in DR Congo points to a UN Security Council resolution passed in March this year that calls on Uganda not to allow its territory to be used by armed groups from the region.
It also points out that under another Security Council resolution Uganda is obliged to hand over to face justice anyone suspected to have carried out human rights atrocities.
In Kampala, I met Justin Lobho, one of the signatories to the MRC document, who used to be in the FNI rebel group in Ituri and disarmed in March.
He says whether you disarm or not you are harassed. He accused people in the Kinshasa government of being responsible for some of the bloodshed in Ituri.
This new group, he said, would make sure it was listened to and denied that it had received support from Uganda.
The same group of Congolese rebels are known to have recently been to the Rwandan capital, Kigali.
Whatever the possible threat posed by the formation of the MRC, the presence in eastern DR Congo of yet another rebel group is unlikely to be welcomed by a population tired of war.