A cessation of hostilities in the 20-year civil war between the Ugandan government and Lord's Resistance Army has expired, with no new deal in sight.
Vincent Otti said the LRA rebels wanted to negotiate
Both sides have warned that they will retaliate if attacked.
A fragile truce has been in place for six months but talks were halted when the rebels walked out in December.
The LRA accuses the Uganda government of violating the truce and says it will fight if President Yoweri Museveni will not talk to them.
"We are not going to renew the truce because there are no peace talks at the moment. But if we are attacked, we shall retaliate and then continue fighting," LRA Deputy Commander Vincent Otti told AFP news agency by satellite phone., a few hours before the ceasefire expired at midnight (2100GMT Wednesday).
"We feel like we want to negotiate peace with the government, but if Museveni refuses to talk, we shall go back to the barrel of the gun and fight a prolonged war."
Leaders of the Acholi people in northern Uganda are making a fresh attempt to reconcile the government and LRA.
They are to meet in the next few days across the border in southern Sudan, to try to restart talks between the two sides
In August last year when the LRA and the Ugandan government agreed to stop fighting, hopes were high that one of the most deadly and savage civil wars in Africa might be coming to an end.
The two sides agreed to meet and talk in southern Sudan.
But negotiations soon stopped because of fundamental disagreement on vital areas like power sharing and reform of the Ugandan army.
International Criminal Court indictments against the LRA leadership for human rights abuses proved another obstacle. Now the LRA claims the Ugandan government has violated the ceasefire.
The Ugandan government alleges that LRA fighters have gone back into the bush in the Central African Republic and the eastern Congo.