Three African armies have launched a joint offensive against Ugandan rebels based in eastern DR Congo, military officials say in Uganda, BBC reported.
Uganda, DR Congo and the government of South Sudan reportedly moved against the Lord's Resistance Army (LRA) in the Garamba region of DR Congo.
LRA leader Joseph Kony, wanted by the International Criminal Court, has recently stalled on a peace deal.
The LRA has led a rebellion for more than 20 years in northern Uganda.
The fighting has displaced some two million people.
Uganda's government has been involved in lengthy peace negotiations with the LRA, but the rebels' leader has demanded that arrest warrants for him and his associates are dropped before any agreement can be struck.
A statement announcing the operation was released in the Ugandan capiital Kampala by the intelligence chiefs of all three armed forces.
The statement said the attack targeted the "terrorists" at their bases in the forested area of Garamba, in the east of the Democratic Republic of Congo, AFP news agency said.
"The three armed forces successfully attacked the main body and destroyed the main camp of Kony, code-named camp Swahili, setting it on fire," the statement said.
Correspondents say the regional governments had hardened their attitudes to Joseph Kony in recent months as the peace process appeared to unravel.
Plans to attack the rebel camps have been under consideration for some time in the event no progress was made in peace talks, Reuters news agency said.
The LRA is known for its violence, in particular the mutilation of those who survive its attacks and the kidnapping of children, who have often been forced into conflict.
A spokesman for the rebels, David Nyekorach-Matsanga, told AFP the attack would be strongly opposed.
"If this is true, it is a highly regrettable provocation and the LRA will retaliate," he said.
"I met with the president of Uganda just this week and he assured me there would no attack on the LRA."
Ugandan President Yoweri Museveni has recently renewed a call for Joseph Kony to sign the peace deal, Reuters reports.