"When someone attacks Adre, where do they attack from? Adre is 400 metres from Sudan, so do you think the attack came from Sudan or from Chad?," he said.
The government has repeatedly accused Sudan of supporting the rebels by allowing them to strike from its territory as part of a widening campaign of regional destabilisation. Khartoum denies the charge.
Humanitarian workers in Adre said the town's hospital had received 120 wounded, at least a third of them civilians.
The rebels said 100 government soldiers and 13 of their own had been killed but there was no independent confirmation.
|"After four hours of violent fighting, [President]Deby's troops were completely destroyed"|
Ali Moussa Izzo, spokesman for the Union of Forces for Democracy and Development
A spokesman for the Union of Forces for Democracy and Development (UFDD), part of a coalition trying to force Deby out of power, said they had reached the centre of Adre after heavy fighting before withdrawing to avoid civilian casualties.
"After four hours of violent fighting, Deby's troops were completely destroyed," Ali Moussa Izzo said.
"There is no more fighting but we still hold the approaches to the town."
In the past, the rebels have usually quickly withdrawn from towns or villages after seizing them, part of a hit-and-run strategy aimed at trying to wear down Deby's army.
Thursday's attack was the first since early December when the government claimed to have wiped out the rebels in a battle at Hadjer Marfain, north of Adre.
Rival militias clash
In separate violence further north near the Chad-Sudan border, government sources told Reuters that around 30 people had been killed and 40 injured since Monday in feuding between rival militias.
The fierce clashes between fighters of the Tama and Zaghawa ethnic groups took place at Djimeze, between Guereda and Hadjer-Marfaine.
The sources said Chad's government sent forces to the area to restore order.
The latest violence came as a UN team continued a mission to evaluate whether to deploy international peacekeepers along the border between Chad and Sudan.
The team, sent by the UN Security Council, visited Chad last week and is currently in the Central African Republic, which has also blamed Sudan for rebel raids on its northeast.