Online forex broker Plus500 said on Tuesday 8,457 customer accounts have been fully reviewed and unfrozen after being forced by UK regulators to freeze them due to concerns about the laxity of its customer registration process.The group, which was acquired by Playtech for £459.6m last week, also started communication with inactive customers encouraging them to submit the appropriate documentation proving they are cleared to trade.Plus500 said in a statement that, despite being too early to anticipate the ongoing behaviour of its customers, 61% have resumed trading and 5% have cashed out all their funds.Meanwhile, the broker continues to work with consultants to ensure new clients are meeting the required procedures.This follows news that the Financial Conduct Authority forced the company to ensure all clients provide proper levels of identification as part of stricter anti-money-laundering (AML) rules.Chief executive Gal Haber said: "We have made progress in reapproving customer accounts during the last week and as a result expect a majority of clients who have completed the remedial AML procedures to be unfrozen within the previously expressed timeline. This will be followed by contacting inactive customers."Shares fell 0.27% to 370.5p on Tuesday at 08:21.