[WASHINGTON] The White House urged Greece and EU leaders on Monday to find a compromise to keep the cash-strapped country in the eurozone, after Greeks voted resoundingly to reject an austerity-based bailout.

"The referendum is over, but our view here at the White House remains the same," said spokesman Josh Earnest.

EU and Greek officials need "to agree to a package of reforms and financing that would allow Greece to be on a path toward debt sustainability but also economic growth," Mr Earnest told reporters.

They should do so "in a way that would allow Greece to remain part of the eurozone," he said.

"This is a European challenge to solve." It was the first official US comment on Sunday's referendum, in which Greeks voted by a 61 per cent majority to reject a bailout deal from the European Union that required more austerity and reform, handing a victory to the ruling radical Syriza party.

President Barack Obama spoke by phone with French President Francois Hollande about keeping Greece in the eurozone.

"The two leaders agreed on the importance of finding a path forward that will allow Greece to resume reforms and return to growth and debt sustainability within the Eurozone," the White House said.

Mr Obama and Mr Hollande also noted the effort will "require difficult compromises from all sides." Meanwhile, US Treasury Secretary Jacob Lew spoke by telephone with Greek Prime Minister Alexis Tsipras and with new Finance Minister Euclid Tsakalotos.

He called for multiparty talks and a "constructive outcome that will allow Greece to make difficult but necessary fiscal and structural reforms, return to growth, and achieve debt sustainability within the eurozone," a statement said.

AFP