BANGUI Heavy weapons fire rang out in the north of Central African Republic's capital Bangui on Monday during inter-religious clashes and the Red Cross said at least four people were killed.
French and African troops have struggled to contain violence between Muslim Seleka rebels and Christian militias that has already killed 1,000 people this month and displaced hundreds of thousands.
"There was heavy weapons fire north of Bangui for a few hours and several neighborhoods were affected," Amy Martin, head of the U.N. Office for the Coordination of Humanitarian Affairs in Bangui told Reuters.
A Reuters reporter in the capital reported shell explosions and mortar fire but it had stopped by late morning.
Heavy arms fire was reported in Bangui during a two-day surge in violence which began on December 5 but shooting in recent days has been limited to sporadic small arms fire.
"In the area (of the clashes) there were four bodies but I'm sure there will be more," Red Cross President Pastor Antoine Mbao Bogo told Reuters on Monday, adding that four other bodies were found in other parts of the capital.
Guy-Simplice Kodegue, spokesman for interim President Michel Djotodia, said earlier that new fighting was between government forces and members of the Christian militia, known as anti-balaka after the local Sango language word for machete.
He did not say whether there had been any casualties.
A local resident who didn't wish to be named said a group of around 40 men armed with Kalashnikov rifles marched through northern Bangui on Monday, despite French-led efforts to disarm the population.
Another resident in a north Bangui neighborhood, Flavier Koma, said Seleka forces began a door-to-door hunt for anti-balaka fighters after the morning clashes.
The country's Christian majority has complained of waves of looting and killing by Djotodia's loose band of militias who seized power in March with the aid of fighters from Chad and Sudan.
Violence intensified in early December after Christian militias launched reprisal attacks on Seleka forces, raising fears of generalized conflict in the country.
The number of internally displaced has swollen to more than 800,000 with the mounting violence, more than 100,000 of them are sheltering in a makeshift camp at Bangui airport.
Kristalina Georgieva, EU aid chief, said that concerted international action was needed to prevent "an appalling tragedy from spiraling further out of control".
UNICEF, the United Nations' children's agency, said on Monday that at least two children had been beheaded in this month's violence.
"More and more children are being recruited into armed groups, and they are also being directly targeted in atrocious revenge attacks," said Souleymane Diabate, UNICEF Representative in the country.
International medical charity MSF said the number of injured people received at its Hopital Communitaire had risen to around 15-20 per day, often with machete wounds.
On Christmas day three armed men entered the hospital, threatening the safety of patients, it said.
"It is totally unacceptable that health facilities are not being respected and are being invaded by armed people who constitute a threat to patients and staff," Thomas Curbillon, MSF's head of mission in Bangui, said on Monday.
Martin Ziguele, a former prime minister and opposition leader, called for the formation of a national commission to bring accountability for crimes.
"There can be no true reconciliation without justice and forgiveness," he said in a statement.
Many say the bloodshed has little to do with religion in a nation where Muslims and Christians have long lived in peace, and have instead blamed a political battle for control of resources in one of Africa's most weakly governed states.
Central African Republic, racked by five coups and numerous rebellions since independence from France in 1960, is rich in diamonds, timber, gold and oil.