Iran on Friday summoned the chargé d'affaires of Switzerland, which represents Washington's interests in Iran, to protest the seizure of an Iranian-flagged tanker by Greece at the request of the U.S. government, which it said was a violation of international laws and the regulations of the sea, according to local media.

The crude oil cargo of an Iranian-flagged tanker that was stopped in Greek waters last month has been seized and is being transferred to another vessel following a request from the U.S., a Greek official said on Thursday.

Switzerland has represented the United States in Iran as the Protecting Power of the United States since 1980. Washington broke off relations with Tehran in 1980 over the hostage crisis that kept 52 American diplomats and citizens trapped at its embassy in Iran for 444 days.