More than 1,000 police officers were involved in the raids, which were directed against members of an international money laundering network. A total of 80 houses, flats, offices and business premises were searched in the raids.

Further details are due to be announced by the Dusseldorf public prosecutor’s office at a press conference on Wednesday afternoon. “The operation is still ongoing,” a police spokesperson said on Wednesday morning.

The office for the prosecution of organized crime at the Dusseldorf public prosecutor’s office is conducting the investigations, which are directed against members of a so-called hawala network, according to the statement.

Hawala banking, which is illegal in Germany, is an informal money transfer system that allows customers to transfer large sums of cash abroad which, if sent through the banking system, would require the approval of the banking supervisory authority.

The suspected money launderers are believed to have transferred more than 100 million euros (115 million dollars) from illegal businesses in Germany to Turkey and Syria.

According to media reports, the money originates from drug trafficking, among other illegal activity, and is also alleged to have been used in Syria to finance terrorism.

The investigation began after a chance find by the police, when officers discovered 300,000 euros in cash hidden in a gym bag during a routine stop on a motorway.