Fighting has broken out in the Central African Republic (CAR), a day after a ceasefire was signed between rebels and the government.
Aid agency MSF says at least 35 people were wounded in Bria, north-east of the capital, Bangui, while the mayor told Reuters that 42 people died.
The truce, signed in Rome on Monday, included an immediate ceasefire.
It was intended to bring armed groups into the political process in exchange for ending attacks.
Thousands of people have been killed and hundreds of thousands displaced in the CAR since mainly Muslim Seleka rebels ousted President Francois Bozize in 2013.
The move triggered a backlash from mostly Christian militias, called the anti-balaka.
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- CAR country profile
MSF's project co-ordinator in Bria, Mumuza Muhindo Musubaho, said fierce fighting erupted in Bria early on Tuesday.
Within three hours "we already had 35 wounded in hospital, mainly injuries from bullets," he said.Image copyright AFP Image caption The ceasefire was brokered by the Sant' Egidio Catholic Community and signed in Rome
Town Mayor Maurice Belikoussou told Reuters that 42 bodies had been taken to hospital.
"There are also bodies in the neighbourhoods that have not been picked up yet," he added.
The peace agreement was brokered by the Sant' Egidio Catholic Community in the wake of years of sectarian violence and the deployment of a long-running UN peacekeeping mission in the country.
More than a dozen militia groups agreed to end hostilities immediately and to co-operate with a truth, justice and reconciliation commission.
But observers say armed groups have yet to show an interest in laying down their arms.
Eyes On Events West Africa correspondent Thomas Fessy says deals have been signed in the past few years but all have failed to bring the country back to peace and stability.