New Delhi, Aug 22 (IANS): The area around CBI headquarters building in New Delhi was virtually turned into a fortress on Thursday as top sleuths continued interrogating former Finance Minister P. Chidambaram inside its premises.

The road leading to the building was barricaded at least 500 meters ahead of its entrance with a huge contingent of policemen standing guard. Incidentally, the new CBI building was inaugurated in the presence of Chidambaram in 2011.

Entry through the barricade was strictly barred except for staff and vehicles with government stickers.

"All thoroughfare has been blocked. Entry is only on furnishing of valid identity proofs. General public have been prohibited from using this route," said a senior cop.

Entry of vehicles through the barricade was only through a proper queue.

Chidamabaram had reportedly spent Wednesday night inside a suite on the ground floor of the CBI building.

Chidamabaram had been whisked to the headquarters of the CBI, near Jawaharlal Nehru Stadium, on Wednesday night after he surfaced at a press conference of the Congress Party.