President Faustin Touadera urged restraint among Bangui's residents.
He has also promised justice, saying the perpetrators and their accomplices will be found and prosecuted.
The Red Cross said the death toll has risen to 19, with 98 wounded.
A priest was among those killed on Tuesday as a church, mosques and health facilities were targeted in the capital's PK5 and Fatima neighbourhoods.
Deeply impoverished Central African Republic has faced deadly interreligious and intercommunal fighting since 2013, with thousands of people killed and hundreds of thousands displaced.
The violence has spread in the past year.
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