According to fire officials, the blaze was reported from the third floor of the building located in the Central Government Offices (CGOs) complex here at about 6.45pm.
A total of six water tenders were rushed to the spot, they said, adding the extent of damage will be known later in the evening.
CRPF sources said some papers and documents of the communication branch located on the floor have been gutted in the blaze and the exact cause of the fire is being ascertained.
No casualties have been reported and senior officials have reached the spot, sources said.
A blaze was reported from the same building in June last year and the public relations office of the force on ground floor was gutted.