WASHINGTON (Reuters) - The U.S. Commodity Futures Trading Commission said on Thursday that as a result of the ransomware attack on ION Trading UK the CFTC's weekly Commitments of Traders report will be delayed until all trades can be reported.

ION Group, the financial data firm's parent company, said in a statement on its website the attack began on Tuesday. Sources familiar with the matter told Reuters the disruption could take days to fix, leaving scores of brokers unable to process derivatives trades.

"The ongoing issue is impacting some clearing members’ ability to provide the CFTC with timely and accurate data," the CFTC said in a statement.

It said the Commitments of Traders report that is produced by CFTC staff will be delayed until all trades can be reported. "A report will be published upon receipt and validation of data from those firms," the CFTC said.

CFTC reports provide a snapshot of investor positioning on various assets.

The commission also said certain reporting firms affected by the ION attack do not have enough information at this time to fully prepare the daily large trader reports.

"Each affected reporting firm should use best estimates in preparing those reports, working with Commission staff, to ensure timely compliance," the CFTC said, adding firms should file revised reports once systems are operational.

(Reporting by Eric Beech; Editing by Caitlin Webber and Chris Reese)