The International Monetary Fund (IMF) said Thursday that Greece would need an extension of its EU loans and a potentially large debt writeoff if it grows more slowly than expected and economic reforms are not implemented. The warning in a preliminary draft of the IMF's latest debt sustainability report came as Greece readies for a Sunday referendum on an international rescue deal that Prime Minister Alexis Tsipras has urged voters to reject. The IMF, which is part of a "troika" that includes the European Commission and European Central Bank that is overseeing the rescue, said that even if Greek policies were to be put back on track, loans made by Europe "will need to be extended significantly" and the country would need further concessional financing. The report was made based on assessments last week before Greek banks were closed and the country defaulted on an IMF repayment.