Supporters of Pope Francis have rushed to his defense after a former top Vatican official launched an unprecedented attack on him, a move they say dangerously escalates a campaign to weaken his papacy by conservatives who condemn him as too liberal.

Francis' supporters say the accusations in Archbishop Carlo Maria Vigano's 11-page public statement aim to pave the way for a conservative pope to succeed him who would reverse his openings to divorced and homosexual Catholics.

In the statement published over the weekend, Vigano, the former Vatican ambassador to Washington, called on Francis to resign on the grounds the pope knew for years about the sexual misconduct of an American cardinal and did nothing.