A Spanish investigative magistrate has opened a probe into possible money laundering at Banco de Madrid SA, a unit of Andorra's Banca Privada d'Andorra accused by the U.S. of helping groups from China, Russia and Venezuela launder money.

The National Court said Tuesday that Judge Fernando Andreu had opened an investigation into the bank and its seven directors following a complaint by a client that said the bank made itself available for clients to launder money and minimized internal controls.

The court said some of the bank's operations may have harmed not only clients and investors but the bank itself and the national economy.

Banco de Madrid is in the process of liquidation after Spain's central bank took over it last month.