The police said in a statement the move, which concerned Italian citizens holding 9,953 financial positions in Switzerland, followed an investigation that last year led to a tax settlement deal between Italy and Credit Suisse AG.

The police declined to say whether the people Italy was seeking information on were Credit Suisse's customers and did not provide further details.

The statement said that 3,297 people had already been identified through a national voluntary disclosure tax amnesty scheme, used by the Italian government to encourage tax dodgers to declare funds held abroad in return for immunity from prosecution.

In December an Italian judge approved a settlement between Credit Suisse and the country's authorities under which the Swiss bank agreed to pay 109.5 million euros.

The tax investigation, started in 2015, was over an alleged fraudulent system used by the bank to transfer money offshore, mainly through the use of insurance policies. The bank's local unit Credit Suisse Italy SpA was not involved in that case.

"Credit Suisse considers the investigation by the Italian authorities into Credit Suisse's cross-border business as closed," the bank told Reuters in an emailed statement.

"The court approval marked the end of the investigation by Italian authorities into Credit Suisse AG's Italian cross-border business for the period from 2008 to 2015," the statement added.

Switzerland's Federal Tax Administration declined to comment, pointing to a confidentiality clause that applies to mutual requests for assistance on tax matters.

(Reporting by Giulia Segreti in Milan and Brenna Hughes Neghaiwi in Zurich; Editing by Greg Mahlich)