WASHINGTON - (AP) - A federal official says MF Global, thesecurities firm led by Jon Corzine, admitted using clients' moneyas its financial troubles mounted.

The official familiar with the conversation says the MF Globalexecutive admitted that to federal regulators in a phone call earlyMonday after regulators raised questions about the company's books.

It is not clear where the money ended up or what it might havebeen used for.

MF Global filed for bankruptcy protection Monday, after a bigbet on European debt threatened to topple it.

The investigation of MF Global Holdings Ltd. is preliminary. Aformal investigation by the company's main regulator, the CommodityFutures Trading Commission, requires a vote by its fivecommissioners.

It isn't clear whether the violations could lead to criminalcharges.

The head of the Chicago Mercantile Exchange said that MF Globalhad violated rules requiring it to keep clients' money in separateaccounts.

Official: MF Global admitted using client money