Putting up a brave front after annulment of amnesty in graft cases to him by Supreme Court, Pakistan President Asif Ali Zardari has vowed to "fight back" as the ruling PPP reposed "full confidence" in his leadership.The beleaguered President made the pledge "to fight back" while chairing a meeting of PPP's central executive committee yesterday to review the fallout of the apex court's decision to scrap National Reconciliation Ordinance (NRO), a controversial law promulgated by ex-military ruler Pervez Musharraf in 2007 which gave amnesty to Zardari and over 8,000 other people in graft cases.Presidential spokesman Farhatullah Babar said,the PPP reposed full confidence in Zardari's leadership and vowed to rally around him at a time when he is the target of criticism and political attacks from all around and to put up a fierce fight in his defence. The party also decided that federal ministers facing graft charges following the scrapping of the NRO by the apex court on Wednesday would defend themselves in court instead of resigning.Zardari said the PPP "will not be blackmailed into asking its ministers to resign merely on the basis of accusations against them". He said, none of the accusations had been proved and there is no reason for anyone to resign "until proved guilty of wrong-doing.