Greece's socialist PASOK party joined the main opposition on Sunday in saying it would not back Prime Minister Alexis Tsipras if he calls a confidence vote following a rebellion in the governing party over a new bailout deal. Tsipras had to rely on opposition groups including PASOK to win a parliamentary majority on Friday in favour of the 86 billion euro bailout programme, Greece's third with international creditors since 2010. By contrast, Tsipras suffered the biggest rebellion yet among anti-bailout lawmakers from his leftist Syriza party, forcing him to consider a confidence vote that would pave the way for early elections if he loses.