Dutch financial services group ING said on Monday it has put its car leasing business up for sale, in a deal Dutch media reported may be worth 4 billion euros ($5.7 billion).

ING is in the throes of a huge restructuring, forced on it as a condition of its 10-billion-euros state bailout in the 2008 financial crisis.

It has sold several assets already to raise money to repay the state, but the car leasing unit had not been earmarked previously as a possible divestment.

Just last week, ING agreed to sell its U.S. online bank to Capital One Financial Corp for $9 billion in cash and stock. It also plans to list its insurance operations in two separate initial public offerings.

ING today confirmed that it is currently reviewing strategic alternatives for ING Car Lease, including discussions with third parties interested in a potential acquisition, ING said in a statement, confirming a report in a Dutch newspaper.

ING declined to give financial details, only saying that the unit operated in eight European countries, has 240,000 cars and employs 1,200 people.

Dutch newspaper Het Financieele Dagblad had on Monday reported that ING's car leasing unit has about 360,000 vehicles, and put a value of 4 billion euros on the operations.

We are positively surprised that ING Car Lease is put up for sale. This is because the divestment of this unit was not part of the ... strategy, said SNS analyst Lemer Salah.

The newspaper said car leasing peers including BNP Paribas' Arval , Rabobank subsidiary Athlon , BMW-Alphabet , Volkswagon's Leaseplan and GE Fleet Services have been approached by ING's advisory banks to discuss a potential deal.

Salah, who said it is positive that ING is fine tuning its business, added that he considers Athlon, Leaseplan and Arval are the main bidders for the car leasing business.

(Reporting by Roberta B. Cowan; Editing by David Holmes/Sara Webb)