LAMEZIA, Italy -- Authorities intercepted letters containing bullets sent to former Italian prime minister Silvio Berlusconi and his successor, Mario Monti, the ANSA news agency reported Friday.

Ten envelopes containing the bullets were intercepted by police in the southern Italian city of Lamezia. Some of the envelopes, discovered late Thursday, were addressed to the editors of major national newspapers in Italy.

The letters were sent by the Armed Proletarian Movement, a little-known far-left group in Italy, AFP reported.

Threatening notes were found in the envelopes addressed to Berlusconi and Monti, reading, "Reconsider the austerity plan or we'll make you pay."

The message added, "We will hit you and it will be a war to the death. We'll make you curse these measures in your blood. You will no longer sleep soundly. The bullets are many."

Italy's lower house of parliament was preparing to put Monti's austerity measures to a confidence vote Friday.

The premier has told Italians that the economic crisis is severe and that they will have to tighten their belts.

The incident followed a series of parcel-bombing scares claimed by the Italian far-left group Federazione Anarchia Informale (Informal Anarchist Federation) this month.

On Monday, Rome mayor Gianni Alemanno also received a letter with two bullets and a threatening note signed by the Red Brigades, a left-wing terrorist organization responsible for a string of violent acts in the 1970s and 1980s.