CBI today arrested a senior IAS officer and his associate in connection with the alleged Rs 340 crore excise duty evasion scam, taking to six the total number of persons held in the case.

A 1983 batch IAS officer, O Ravi, Joint Secretary (Disaster Management), Ministry of Home Affairs, was placed under arrest by CBI after hours of grilling by agency sleuths, official sources said.

The Home Ministry has asked the Department of Personnel and Training (DoPT) to suspend Ravi. The suspension orders are likely to be issued soon.

His associate Rakesh Rastogi, who is alleged to have been keeping his wealth believed to have been accumulated through illegal means, was also arrested by the CBI.

The agency has conducted exhaustive searches on his residential and official premises in connection with the scam.

A case under various sections of IPC and the Prevention of Corruption Act has been registered against Ravi, two excise inspectors --Ramesh Mahyavanshi and Vijay Halpati-- and sub-inspector Suresh Dhodi, CBI has said.

CBI had arrested owner of Royal distilleries Ashok Khemani and three excise officials last night. Khemani was arrested from a posh hotel in the national capital while the others were arrested from Daman.

Ravi is alleged have taken a bribe of Rs 25 lakh to get the Daman administrator transferred, a CBI spokesperson said.

The directors of six distilleries --Royal, Jupiter, Krimpy, Silver Star and Dharmesh and some unknown persons -- were also booked for alleged fraud.

"It has been alleged that in order to evade excise duty and VAT, the distilleries of Daman in connivance with the officials of the excise department resorted to under-reporting of production by preparing fake documents," the spokesman said.

CBI has conducted searches at 36 places of the accused persons at Daman, Mumbai and New Delhi.