The rebel Lord's Resistance Army (LRA) has responded poorly to a recent initiative by mediators attempting to peacefully end the 19-year-old war in northern Uganda between the insurgents and government forces, sources said.
Launched by Uganda's four main donors: Britain, the Netherlands, Norway and the United States, the initiative involved broadcasting radio messages to the rebels inviting them to contact the chief mediator of the peace process, Betty Bigombe.
The messages also announced the creation of a special radio monitoring post at which the rebels could pass messages to Bigombe to re-establish contact with her.
"We are in discussions with the Ugandan government about peace but we would like to impress upon you that it is absolutely vital that you re-establish contact so that the opportunity for peace talks is not lost," the radio messages said.
"Your concerns can and should be issues for discussion. But it is impossible to do this if you do not re-establish contact - we urge you to do so without delay," they added. "This is a window of opportunity that may be closing rapidly."
However, relief workers in northern Uganda said the southern Sudan-based rebels had been reluctant to heed the messages.
"The response has been much less than we expected," one relief worker in the northern town of Gulu, 380 km north of the capital, said on Thursday. "What we have got are small time telephone calls."
According to the source, "nothing tangible has been discussed during the small time telephone contacts with the rebel group".
The chief mediator, Bigombe - a former Uganda government minister - told IRIN the LRA had contacted her by phone in the past few weeks, but declined to give details of her talks with them.
Another relief worker said: "We shall keep on trying again and again because this is a peace process that cannot be taken to its logical conclusion in a short time. It takes months and sometimes years."
Meanwhile, renewed clashes between the rebels and the Ugandan army have claimed more than 20 lives both in northern Uganda and southern Sudan since Monday.
"Around midday [on Wednesday] inside Sudan in Kit Valley, about 40 km from our border, we caught up with an LRA group of about 50 and killed between 15 and 20," Lt Col Shaban Bantariza, Ugandan army spokesman, said.
"We used both helicopter gunships and ground forces against the LRA fighters and recovered about 20 bodies," he added.
Bantariza said another 10 rebels were killed on Monday near Kitgum town, 450 km north of the capital, Kampala, when the army attacked a group led by LRA second in command, Vincent Otti.
"He was carrying food to Sudan," the spokesman added. "We ambushed them, beat them up and killed 10."
Since 2002, the Sudanese government has allowed Uganda to pursue the rebels inside its territory.
The LRA has fought the Ugandan government for nearly two decades, ostensibly to replace President Yoweri Museveni's administration with one based on the biblical 10 Commandments.
However, the rebel group is best known for its brutality against civilians, tens of thousands of whom they have killed, maimed and abducted. Some 1.6 million people have been displaced from their homes by the conflict. The UN estimates that the LRA has abducted more than 20,000 children to fight in its ranks or serve as porters and sex slaves.
Talks to end the rebellion have achieved very little progress over the year, mainly due to the mistrust between the two parties. The mediators maintain, however, that the talks were still on course.
The Ugandan government has a three-pronged approach to fighting the LRA: military means, peace talks and immunity from prosecution for rebels who surrender to the government. Museveni has been accused, however, of preferring the military option, and told IRIN he did not "believe in the magic of the peace talks".