The Serious Fraud Investigation Office (SFIO) has narrowed on five arms of Infrastructure Leasing & Financial Services (IL&FS)that may have been involved in fund diversion and mismanagement, the Economic Times reported on Wednesday.

Indian government took control of the debt-laden IL&FS last week after defaults on a string of debt obligations triggered wider concerns about risks in the country's financial sector. 

The five companies under SFIO probe are IL&FS Transportation Networks Ltd ILFT.NS , IL&FS Financial Services Ltd, IL&FS Energy Development, IL&FS Tamil Nadu Power and IL&FS Engineering and Construction Company ILFE.NS , the paper said.

The five firms constitute for more than 50 per cent of the entire group's revenue and may have diverted funds in projects that were worth 300 billion rupees ($4.04 billion), ET reported, citing two government officials.

The Institute of Chartered Accountants of India (ICAI) has also begun probing the matter and issued notices to statutory auditors seeking an explanation, it said.

IL&FS Group, SFIO and ICAI did not immediately respond to requests seeking comment. ($1 = 74.3300 Indian rupees)

(Reporting by Mekhla Raina and Tanvi Mehta in Bengaluru; Editing by Gopakumar Warrier) ((Mekhla.Raina@thomsonreuters.com; +918067491775;))