ATHENS - Voting opened on Sunday in a Greek election that could decide whether the heavily indebted country remains in the euro zone or heads for the exit, potentially unleashing shocks that could break up the single currency.

In an election fought over the punishing austerity package demanded by international lenders as the price of keeping Greece from bankruptcy, opinion polls showed the radical leftist SYRIZA party, which wants to scrap the deal, running neck and neck with the conservative New Democracy, which broadly backs it.

The European Union and International Monetary Fund have insisted that the conditions of the 130 billion bailout accord agreed in March must be accepted fully by a new government or funds will be cut off, driving Greece into bankruptcy.

Sunday's election is a re-run of an earlier vote on May 6 which produced no clear winner and forced voters back to the polls for a vote that is seen as a referendum on the future of the single currency.

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