Italys ex-prime minister Matteo Renzi resigned as head of the centre-left Democratic Party (PD) on Sunday, kicking off a leadership battle as the countrys ruling party grapples with the threat of a schism.
Renzi, who stepped down in January after losing a key referendum, said he would run to win back his post as party secretary, which would put him in pole position to become prime minister once more should the PD win approaching national elections.