A top Ugandan rebel has threatened to go back to war if a new venue is not found for stalled talks in south Sudan.
The rebels are supposed to assemble in Sudan this month
Vincent Otti, deputy leader of the Lord's Resistance Army (LRA), made his comments after Kenya rejected calls to host the peace talks on Sunday.
The rebels asked for a new venue after Sudan's president accused them of atrocities in the south and threatened to evict them last month.
The talks were considered the best chance to end the 20-year conflict.
The LRA has abducted thousands of children during its two-decade rebellion and some 2m have fled their homes.
"If they cannot find another venue, then I will go back... and start war," Mr Otti told Reuters news agency from his base in northern Democratic Republic of Congo.
"We are ready to invade Uganda."
Reports say that LRA fighters have been withdrawing from assembly points in southern Sudan where they are supposed to have gone to since a ceasefire agreement with the Ugandan government was signed last year.
The LRA said they would not take part in further talks unless they were hosted by Kenya or South Africa, as they no longer felt welcome in Sudan.
South Sudan's Vice-President Riek Machar and mediator of the talks denied that the LRA had been asked to leave.
Last week, diplomatic missions in Uganda called on the government and the rebels to resume the talks due to start on 28 February.
Four of the LRA's top commanders are wanted on war crimes charges by the International Criminal Court.
Over the weekend, President Yoweri Museveni warned the LRA to continue with the mediation in south Sudan.
"I hope the LRA will... be serious with the talks," he told a radio station in Gulu, Uganda's Monitor newspaper reports.
"If they don't, we will have to first liaise with the government of south Sudan, DR Congo and the UN secretary-general to work out on their arrests."
The LRA have indicated that no deal can be signed while warrants for their arrest remain in place.