The government had said previously that the troops' movement was part of a rotation of forces rather a withdrawal.
"They are also here to secure the constitutional referendum," the spokesperson said, declining to say how many troops had arrived.
A senior CAR military official in the capital told Reuters that hundreds of troops had arrived.
CAR President Faustin-Archange Touadera, who was first elected in 2016, and won reelection in 2020, turned to Russia for help to tackle the rebel groups.
He is on the campaign trail for the constitutional referendum which, if passed, could remove a two-term presidential limit and enable him run again.
Persons:
wagner, Faustin, Russia's Wagner, Wagner, Yevgeny Prigozhin, Albert Yaloke Mokpem, Francois Bozize, Touadera, Judicael Yongo, Bate Felix, Anait Miridzhanian, Alison Williams
Organizations:
Central, Reuters, Thomson
Locations:
Bangui, Central, Read, BANGUI, Central African Republic, Russia