The UK's financial regulator has handed banks and financial businesses a deadline of next week to check if they have links to a law firm at the centre of the Panama Papers leak.
The Financial Conduct Authority has told banks they have until April 15 to investigate whether they have ties to Mossack Fonseca or firms which are managed by the company, according to a letter seen by the Financial Times.
It comes after a leak of more than 11 million documents from the law firm in Panama sparked allegations of money laundering and tax evasion by high-profile figures across the globe.
The FCA has called on financial firms to reveal what action they are taking after the Panama Papers leak revealed that more than 500 banks, including their subsidiaries and branches, registered nearly 15,600 shell companies with Mossack Fonseca.
The letter, which has been sent to about 20 businesses, states: "Beyond April 15 we will require updates on any significant issues or relationships identified and a full response, detailing findings, when your investigation is concluded."
HSBC, Credit Suisse and the Royal Bank of Scotland-owned Coutts Trustees denied claims earlier this week that they were helping clients avoid tax by using complex offshore structures.