EU President Donald Tusk warned Wednesday that Greece and its European partners now faced the very last chance to reach a rescue deal needed to keep debt-ridden Athens in the eurozone.

"Without unity on Greece we will wake up in four days in a different Europe; this is really and truly the final wake-up call for Greece and for us, our last chance," Tusk told the European Parliament in Strasbourg, where Greek Premier Alexis Tsipras earlier promised progress after months of fruitless talks.