Former Italian Premier Matteo Renzi has resigned as Democratic Party leader in a bid to win a stronger mandate before the national election.
As promised, Renzi told fellow Democratic leaders at a meeting on Sunday that he was resigning.
But he insisted he will not submit to what he called the "blackmail" of a more left-leaning faction threatening a schism if he again seeks the top party post.
The national election, due in early 2018, might come earlier if Premier Paolo Gentiloni loses control of a frequently squabbling centre-left parliamentary majority.
The populist, anti-euro 5-Star Movement aims to gain national power for the first time. It is Parliament's second-biggest party, after the Democrats, who govern in a centre-left coalition.