NEW DELHI, INDIA: India's federal investigating agency, the Central Bureau of Investigation, is conducting a search in the offices of the telecoms ministry to probe the manner in which wireless radio spectrum was given to telecommunications firms, a spokesman for the agency said on Thursday.

It is for possible "irregularities in 2G spectrum distribution," Harsh Bhal, spokesman for CBI said, without giving further details.

A spokesman for the telecom ministry was not immediately available for comment.

Telecom firms in India offering second-generation (2G) mobile services get some spectrum to start with after they take a telecoms licence. Subsequent allocation is done in slabs linked to the firm's subscriber numbers.

India had awarded several new telecom licences in 2008.