Oil prices eased in Asia Friday ahead of a weekend bailout reform referendum in Greece that could determine its future in the eurozone.
West Texas Intermediate for August delivery was down 24 cents at $56.69 while Brent North Sea crude was 15 cents lower at $61.92.
Greek voters will be asked to vote either "yes" to a bailout package offered by creditors in exchange for tougher austerity measures, or "no" in support of the leftist government`s bid to gain better terms.
Prime Minister Alexis Tsipras called the poll after breaking off debt reform talks with the country`s creditors -- leading it to default on a loan repayment Tuesday.
European leaders have warned that it is effectively now an in-out vote on Greece`s future in the eurozone.
"Negotiations (between Greece and lenders) appear to have ground to a standstill with everyone awaiting the results of Sunday`s vote," said analyst Nicholas Teo of CMC Markets in Singapore.
"With either outcome, global markets continue to remain on tenterhooks as any near-term resolution of the situation there remains a distant prospect."
The International Monetary Fund said Thursday that Greece needs 50 billion euros ($55 billion) over the next three years, while it has also slashed 2015 economic growth forecast to zero.
