Florence, December 10 - Florence Mayor Matteo Renzi, who recently lost a bid to lead Italy's center-left Democratic Party (PD), on Monday said he wasn't interested in joining ranks with ex-premier Silvio Berlusconi's People of Freedom (PdL) party in upcoming general elections. Earlier Monday Berlusconi, who has announced he will lead his party into national elections for a sixth time, said in an open statement he would leave the ''door open'' for the up-and-coming PD politician should he be interested in making common cause with the center-right party. In a statement on his Facebook page Renzi, who lost the PD leadership primaries to current party chief Pier Luigi Bersani, responded to Berlusconi: ''Dear Premier Berlusconi, I've already told you twice in person. Things can be bought, people no. At least, not everyone. Myself included. If you left the doors open for me, take my advice: close them. They're not needed. Ciao''. Bersani said: "After the primaries we are all in better health, we will fight the battle together with Renzi. "I invite Berlusconi not to stoop to the ridiculous, even though it is a place he has amply frequented". Italy's political parties were in full pre-election swing Monday after interim Premier Mario Monti on Saturday said he would resign as soon as the 2013 budget was approved. Monti's earlier-than-expected resignation means elections will now be held sometime in February, sooner than the March-April timeframe previously expected. Berlusconi, whose resignation as premier just over a year ago amid ''bunga bunga'' scandals and a skyrocketing spread between Italy's 10-year bonds and German paper made way for Monti to lead a technocratic government charged with carrying out unpopular but urgently needed economic reforms, confirmed Saturday he would once again lead his party in elections.