ROME, Ramadan 25, 1434, Aug 3, 2013, SPA -- Politicians in Italy's fragile coalition government traded increasingly heated barbs on Saturday over a tax conviction that threatens the political future of centre-right leader Silvio Berlusconi, Reuters reported. The former prime minister has told his party to demand reform of the justice system - which he maintains found him guilty of tax fraud because of political bias - or withdraw from a delicate coalition with the centre-left Democratic Party (PD) that has so far lasted three months. Financial markets have shrugged off the upheaval until now, but strife in the coalition threatens efforts to revive an economy mired in its longest post-war recession. On Friday, five ministers from Berlusconi's People of Freedom (PDL) party said they were ready to resign if needed, and senior party officials agreed to lobby President Giorgio Napolitano to issue a pardon. The party has called a Sunday demonstration in central Rome in support of Berlusconi. Deputy Economy Minister Stefano Fassina, a senior member of the Democratic Party, called the request for a pardon "an unacceptable provocation, as is the request to put the judiciary under political control." Fassina told television SkyTG24 on Saturday: "Either the PDL returns to normal democratic channels, or the PDL ministers who threatened to resign should do it." The tax conviction could put Berlusconi under house arrest or in community service for a year and cost him his seat in parliament after two decades as the dominant force in Italian politics. -- SPA 20:42 LOCAL TIME 17:42 GMT www.spa.gov.sa/1134585