The mini-summit will bring together the roughly 15 European leaders most involved in the CAR and as many African leaders, including South Africa's Jacob Zuma, Chad's Idriss Déby and Congo's Denis Sassou Nguesso, on the first day of the fourth European Union-African Union summit.
It will discuss how to "restore security and stop the killings", sources said.
On Thursday EU foreign policy chief Catherine Ashton deplored an "escalation of violence", which has cost about 20 lives, over the last few days and called for rapid international action.
But a European intervention force, agreed on France's insistence, is having trouble assembling the 500 soldiers promised and is expected to arrive in April, rather than in March as originally planned.
A meetiung of European defence ministers is set to discuss new contributions on Friday.
Germany has refused to send any soldiers but has recently promised to send two Antonov military transport planes.
France has proposed that the UN slap sanctions on former CAR president François Bozizé and his son Jean-Francis for their alleged support to Christian anti-balaka militias.