Political rivals on both the right and left made gains in local elections at the expense of Greek Prime Minister Andreas Papandreou's Panhellenic Socialist Movement. Conservative challengers got more than 42% of the votes cast Sunday in the three major cities--Athens, Piraeus and Salonika--and support for incumbent Socialist mayors declined to about 30%. Communist candidates won just over 20% of the vote in each of the three cities, according to nearly complete returns reported by the Interior Ministry. Runoffs will take place Sunday. Analysts said voters are unhappy with Papandreou's austerity policy.