Switzerland’s banks have begun reporting suspicious account activity among some of their Saudi Arabian clients to the Swiss Money Laundering Reporting Office, part of the federal police service, say people close to the situation.

Lawyers acting for the banks have submitted information over the past week and expect several dozen submissions to be made in total, two people involved in the process said.

The exercise reflects the banks’ nervousness about being found in breach of rules governing money laundering and corruption. It follows the arrest in Saudi Arabia last month of more than 200 people, including some of the country’s richest businessmen and princes. They were detained at the Ritz-Carlton hotel in Riyadh as part of an anti-graft operation launched by Crown Prince Mohammed bin Salman, the kingdom’s powerful heir apparent.