Rome, May 10 - The leader of Italy's anti-establishment 5-Star Movement (M5S) struck back at Premier Enrico Letta Friday, calling him "a kept man of politics" for being the nephew Silvio Berlusconi's long-time right-hand man, Gianni Letta. "How should I perceive someone who's a professional nephew? We won't accept his moral lessons, not from a man who holds on to 46 million euros in public campaign finances," said Beppe Grillo. The M5S party refuses to accept any public funds for its campaigns unlike Letta's center-left Democratic Party (PD). Earlier in the day, Letta lashed out at Grillo after the opposition leader accused the fledgling government of committing a "coup d'etat" when it formed a broad, left-right coalition that includes members of ex-premier Silvio Berlusconi's center-right People of Freedom (PdL) party. Letta called Grillo's comments "totally unacceptable" in a press conference held with European Parliament Speaker Martin Schulz.