Switzerland is stepping up scrutiny of its banks in response to the Panama Papers which prompted a global outcry over allegations of tax avoidance.

Thomas Bauer, the President of Swiss financial watchdog FINMA told Swiss newspaper NZZ am Sonntag on Sunday that “we want to know which banks have used the services of the Panamanian firm and whether Swiss laws were broken.

Without specifying names, he said “we’ve already contacted Swiss financial institutes.

Switzerland is the world’s largest centre for offshore wealth, with Boston Consulting Group estimating that around 2.5 trillion dollars in foreign assets was kept with the country’s banks in 2014.

FINMA signaled a crackdown on money laundering on Wednesday and was now calling for authorities around the globe to set standards that would prevent abuse.

Other states and organisations such as the European Union or the OECD also needed to make efforts to establish similar regulations everywhere, Bauer said.

Branches of Swiss lenders including UBS (UBSG.S) and Credit Suisse (CSGN.S) were mentioned in the leaked documents as being among the main banks that requested offshore companies for clients.

However, both banks had denied wrongdoing in connection with the practice.