"The whole Chadian contingent will be sent to secure the north in the next few days," Misca spokesperson Lieutenant Colonel Ndong Toutoune told the AFP news agency.
The announcement came after exchanges of gunfire were reported in Bangui, which remains tense despite the presence of Misca and French troops.
Sustained gunfire erupted near the airport, where hundreds of people have taken refuge, and on Wednesday morning Burundian troops were patrolling the PK12 neighbourhood after overnight shooting and explosions.
Misca has launched an inquiry into incidents involving Chadian troops this week.
Chadian soldiers opened fire on stone-throwing Christian demonstrators on Monday, killing one and wounding 40.
And the head of the Burundian contingent said that on the same day Chadian soldiers threw a grenade and opened fire on some of his men.
Some Burundians returned fire, wounding three Chadians, he said.
Chad has contributed 850 troops to the 3,700 Misca force but many Central Africans accuse it of meddling in their country's affairs with Christians accusing the Chadians of favouring the Muslim Séléka militias.
Muslims demonstrated against the French on Tuesday, accusing them of failing to disarm Christian anti-balaka armed groups.
At a Christmas Eve press conference interim President Michel Djotodia appealed for peace.
"Love each other," he begged his compatriots. "You can find that in the Bible and the Koran."
Djotodia announced a ban on "all illegal marches" and accused deposed president François Bozizé of stirring up sectarian violence.