The M23 has been calling for talks with the government in Kinshasa.
The ceasefire declared in eastern Democratic Republic of Congo by the M23 rebel group on Tuesday did not hold as clashes were reported in some villages in Masisi territory, North Kivu.
This is the latest failed ceasefire commitment.
Fighting resumed just hours after M23 issued a press release announcing an “effective ceasefire”.
By 12pm Tuesday, the M23 had said it had decided to stop fighting, adding that the decision was in line with consultations between them and Angolan President João Lourenço, the mediator in the Congolese crisis through the Luanda peace process.
M23 also said that the ceasefire was meant to comply with the "various regional summits held in Bujumbura, Nairobi and Addis Ababa, all aimed at finding a peaceful solution to the ongoing conflict in eastern DRC".
Angolan President João Lourenço had ordered the establishment of an ad hoc verification mechanism to ensure compliance with this decision.
Mr Lourenço had urged the rebels and the Congolese government to respect the ceasefire calls. But an attack on a camp belonging to Burundian troops on Monday evening put a blot on the promise to stop fighting.
In Kinshasa, President Félix Tshisekedi had on the weekend already expressed "doubts about the sincerity of this umpteenth ceasefire commitment". He spoke while receiving French President Emmanuel Macron.
"We are waiting to see," the Congolese leader said, arguing that "several ceasefire commitments have been announced without being respected".
The French president had said that this time "those who would not respect the ceasefire would face sanctions".
The M23 has been calling for talks with the government in Kinshasa. In their communiqué, the rebels say that the ceasefire is to "pave way for direct dialogue with the government in Kinshasa".
All the summits of the heads of state of the East African Community have always called for a ceasefire and the withdrawal of the rebels from the conquered areas.
But in its statement, the M23 movement did not mention any planned withdrawal from occupied areas.