French police have arrested a 42 year-old man suspected of sending death threats to President Nicolas Sarkozy and other senior politicians, a police source said on Wednesday.

The man, from the southern city of Montpellier, was reported to authorities by someone who knew him, the source, who could not be named, said.

Sarkozy, several of his ministers and other politicians received envelopes within the past two weeks containing a 9mm cartridge and identical letters from an unknown sender with threats like "you are all dead men walking".

The anti-terrorist unit of the Paris prosecutors' office as well as anti-terrorist police in Paris and the southwestern district of Herault were put in charge of the investigation.