BERLIN: German firms have lost millions of euros to organised crime in a scam dubbed "CEO Fraud" that uses faked memos from top executives to entice accounting personnel to transfer funds, Germany's federal cyber agency said on Monday.

The BSI agency said officials investigating the new scam had secured a list of 5,000 potential targets and were notifying those individuals.

Organised criminals were using the information they gleaned from social media networks, public company websites, job sites and even calls to the companies to fake the contact information for chief executives and other top executives.

BSI said the Federal Criminal Police Office estimated that the scam had already cost firms millions of euros in recent months.

The scam targets personnel in the accounting and auditing departments of a company who were authorised to transfer funds, often using time pressure and warnings about an alleged "secret project" to manipulate them to carry out the bogus orders.

BSI President Arne Schoenbohm urged companies who had fallen prey to the scam to cancel the transactions and notify police.

He also urged companies to warn all those authorised to carry out financial transactions about the scam.

BSI did not identify affected companies.