Greece's once-dominant Socialist party is electing its next leaders as it works to expand cooperation with centrist politicians and recover the public support it lost during the country's catastrophic financial crisis.

Nine candidates are hoping to be elected leader of a new alliance between the Pan-Hellenic Socialist Movement, or PASOK, and centrist party Potami. The current leaders of both parties are running for the post.

The candidates wound up their campaign appearances on Friday. A runoff likely will be needed after a primary-style vote on Sunday.

Founded by late Prime Minister Andreas Papandreou, PASOK won a landslide election victory in 2009 under his son, George Papandreou. Greece slid into a major economic crisis weeks later.

Most Socialist supporters shifted to the left-wing Syriza party, headed by Prime Minister Alexis Tsipras.