France has opened an investigation into death threats against three Israeli athletes after threatening emails were sent to the Olympic delegation, the Paris prosecutors office said on Sunday.

Interior Minister Gerald Darmanin reported the incident and the investigation will be led by the national anti-online hate body, the office added.

According to a source close to the case, no link with Iran or another foreign country has yet been established.

There is also no link between this incident and the illegal leak of Israeli athletes private data on social media on Friday.

Israel on Thursday warned Franceof potential threats from Iran-backed groups against Israeli athletes and tourists during the Paris Games.

French police are giving Israeli athletes round-the-clock personal security within the Athletes Village and during travel to Olympics sites.

France has mounted a vast security operation for the Olympics that began on Friday and run to August 11, with around 18,000 troops deployed in addition to regular police. (AFP)