Rome, February 28 - Senator Sergio De Gregorio admitted to accepting three million euros in bribe money from ex-premier Silvio Berlusconi to destabilize Romano Prodi's 2006-2008 government by defecting from the centre left and joining Berlusconi's party, prosecutors said Thursday after investigation results were shared in the Senate and the House. "The deal was made in 2006," Naples prosecutors quoted the Senator as saying. "My meeting at (Berlusconi's Rome home) Palazzo Grazioli was to agree on the sum of three million euros, which began coming in immediately". Prosecutors said De Gregorio came forward with the allegations in December. He is said to have first accepted two million euros in untraceable installments of 200-300,000 euros from Berlusconi associate Valter Lavitola, De Gregorio's partner in the running of daily newspaper L'Avanti! who was sent to prison in Naples in April after spending over six months in South America as a fugitive of Italian justice. After eventually joining Berlusconi's center-right People of Freedom (PdL) party in a deal, De Gregorio became an outspoken opponent of his former PD party with the aim of bringing it down, De Gregorio told prosecutors. Earlier Thursday a safety deposit box in Berlusconi's name was seized by Italian police and the three-time Italian premier was summoned to appear before Naples prosecutors on March 5. The PdL said the move signalled that some prosecutors have resumed their alleged judicial "persecution" of Berlusconi, a claim the magistrate's union ANM denied. Lavitola and Berlusconi are being probed in a separate case regarding allegations they induced a witness to lie to investigators about alleged sex parties at the former premier's home. Berlusconi is also on trial in Milan over accusations he paid for sex with an underage Moroccan dancer, and is accused of abuse of office in the same case. Berlusconi is appealing against a one-year conviction he was handed last year for tax fraud on film rights for his Mediaset TV group. The ex-premier has also been indicted over accusations he was involved in the publication of an illegally obtained wiretap. In the ongoing and several other previous trials, Berlusconi has always denied wrongdoing, claiming he is the victim of a minority group of allegedly left-wing prosecutors and judges who he says are persecuting him for political reasons. Berlusconi has been tried some 30 times but has only been convicted three times - verdicts that were either timed out or overturned on appeal - prior to the Mediaset fraud verdict. Earlier on Thursday, prosecutors in the northern city of Reggio Emilia said they had opened a probe into a letter Berlusconi sent to millions of Italians about an election pledge to pay back the IMU property-tax. Berlusconi was accused of attempting to buy votes with the pledge by rival politicians, who complained the letter was deceptive as it looked like an official document informing people about how to obtain a rebate, rather than an election pamphlet. Rome prosecutors are also investigating after a similar petition.