French President François Hollande left Nigeria for the Central African Republic (CAR) on Friday morning. He was set to address French troops stationed there as well as meeting CAR Interim President Catherine Samba Panza and religious leaders.
French troops stepped up security in Bangui after Hollande announced the surprise visit on Thursday in Nigeria, where he was attending a summit with African leaders.
It will be the second time that Hollande has visited the CAR since he ordered the French force, which now stands at 2,000, to go to the country to stem sectarian violence in December.
The decision comes a day after the French parliament gave Hollande approval to continue his campaign in the CAR beyond four months.
Another 400 French troops arrived on Thursday for peace-keeping missions and to disarm militia groups.
The European Union's political and security committee on Thursday agreed an operational plan and rules of engangement for a European force in the CAR.
Although so far only three members states have confirmed to take part, the force is expected to be between 800 and 1,000-strong, larger than the 500-600 initially suggested.
It is not likely to be deployed before the end of April.
Earlier in the week the UN warned that 15.000 people were surrounded and under threat of armed attack
In Nigeria Hollande declared France's solidarity with the country in its battle against the Islamist rebel group Boko Haram, drawing parallels with the French intervention in Mali.
"Today Nigeria faces terrorism targeting civilians from Boko Haram," he said in a speech in Abuja. "I think of what happened a few days ago when a school was attacked, the children murdered and villages looted. I also think about the hostages that have been captured by this group. So I assure you, Mr President, your fight is also our fight. We'll always be ready to provide you with our political support, but also our assistance when necessary. The fight against terrorism is also one for democracy."
Hollande was the guest of honour at celebrations to mark 100 years since Nigeria's unification but a meeting to discuss the economy with President Goodluck Jonathan was dominated by security after Boko Haram attacks on several villages in the north.
In Abuja Hollande discussed the situation in the Sahel with Niger's President Mahamadou Issoufou, Gabon's Ali Bongo, Chad's Idris Déby and Mali's Ibrahim Boubacar Keta.