The Democratic Republic of Congo has rejected Ugandan calls for a joint military operation to attack the rebel Lord's Resistance Army (LRA).
The Ugandan army has been fighting the LRA for 19 years
Top government official Antoine Ghonda said the LRA had now left DR Congo and said it was "out of the question for Uganda to send troops into the DRC".
The LRA has been active in northern Uganda and southern Sudan for 19 years.
Last month, a group of LRA fighters crossed into lawless eastern DR Congo, where several militias are operating.
The UN peacekeeping mission in DR Congo, Monuc, said the group had left but Uganda believes some stayed behind, reports the AFP news agency.
Uganda Foreign Minister Sam Kutesa said the rebels' move into eastern DR Congo had brought a new dynamic to a regional problem, which needed to be solved.
He said Monuc should also be involved.
He was speaking at a regional security conference near Uganda's capital, Kampala, but there has been no response from other ministers.
"We should co-ordinate first and then operate jointly because of our accumulated knowledge and experience with the LRA," Mr Kutesa told regional ministers.
"Without our involvement, this problem will not be solved."
The BBC's Will Ross at the conference said the discussions by regional ministers on how to deal with the LRA will be welcomed by the international community, which had become extremely concerned about Uganda's earlier threat to send its troops into DR Congo without consulting its neighbours.
The UN force is trying to disarm all the rebel groups but has so far had limited success.
Officials from the United States are also attending the talks at the Ugandan resort of Munyonyo on Lake Victoria.
In recent months the US government has increased its involvement in the Congolese peace process, resulting in regular meetings between the governments of Uganda, Congo and Rwanda.
Uganda and Rwanda both sent troops into DR Congo during the civil war of the 1990s.
The LRA under Joseph Kony has been waging a war with no clear agenda for 19 years.