* Fighting outside Seleka rebel-held town
* Militias seen regrouping, renewing leadership
* Memorial held for French reporter killed this week
By Crispin Dembassa-Kette
BANGUI, May 15 (Reuters) - At least 31 people, many of them civilians, were killed in clashes between Christian and Muslim fighters in Central African Republic this week, a local priest and Red Cross officials said on Thursday.
Fighting broke out on Monday outside Dekoa, a town 300 km (190 miles) north of the capital Bangui, when fighters from Seleka, the mostly Muslim rebel movement that seized power last year, attacked a roadblock set up by militiamen of the Christan anti-balaka group.
"Yesterday, Red Cross volunteers collected 21 bodies, most of them civilians. Others were anti-balaka," Father Everaldo de Souza, the local Catholic priest, told Reuters.
Another 10 bodies clothed in military fatigues, believed to be Seleka fighters, were discovered in a mass grave, the priest said, adding that some people wounded in the fighting had fled into the bush. Another woman was killed in Dekoa early on Thursday, he said.
Central African Republic's national Red Cross confirmed that its workers had counted around 30 bodies in Dekoa on Wednesday after having initially been barred from entering the town by Seleka fighters.
It is not the first time that Dekoa has been hit by the intercommunal violence which has forced almost a quarter of Central African Republic's 4.6 million population from their homes.
At least 13 people were killed when anti-balaka forces - who have a strong presence in the countryside - attacked the Seleka-held town last month.
Around 50 African Union peacekeepers are deployed in Dekoa, according to town residents. A spokesman for the mission was not immediately able to confirm if the troops had intervened during Monday's fighting.
Seleka rebels seized power in the majority-Christian former French colony in March 2013 but stepped down under international pressure earlier this year.
Since then the "anti-balaka", or anti-machete, militias have intensified revenge attacks against Muslims, and Seleka fighters have regrouped in the north where they have solidified their control.
Rival anti-balaka groups are vying for control of their own loosely affiliated militia movement in the hopes of winning political posts in a new interim government.
One of the dominant anti-balaka factions met in Bangui on Thursday.
"We are in favour of dialogue with Seleka. We will seek to meet their leaders and come up with a common declaration for reconciliation," said Sebastien Wenezoui, who was chosen as the faction's national coordinator.
About 100 soldiers, diplomats and journalists attended a memorial ceremony at Bangui's military airport on Thursday for Camille Lepage, a 26-year-old French journalist who was killed near the border with Cameroon this week. (Writing by Joe Bavier and Emma Farge; Editing by Robin Pomeroy)