Germany's Foreign Ministry says the Swiss ambassador has been called in for talks following the arrest last week of a Swiss national on spying charges.

The Foreign Ministry said the ambassador was asked Tuesday for more details about the spying suspect, a 54-year-old identified only as Daniel M., "in the interests of the German-Swiss friendship."

After his arrest in Frankfurt on Friday, prosecutors said M. was suspected of espionage activity in Germany since 2012.

The Welt newspaper reported Sunday M. was sent to Germany by Switzerland's intelligence agency to identify German tax investigators involved in the purchase of confidential Swiss bank client data.

Germany has in the past bought the names of Swiss banking clients to determine if they were cheating on their taxes.

Swiss officials have declined comment.