The finance ministers of Germany and France said Saturday they were hopeful of a deal soon to move Greece's bailout ahead, reiterating that the IMF needs to be involved.

Speaking a day after the International Monetary Fund questioned the viability of current proposals, Germany's Wolfgang Schaeuble said that a resolution between Athens and its official lenders could be struck following next weekend's meeting of European finance ministers in Amsterdam.

Schaeuble said that even before arriving in Washington this week for the Spring Meetings of the IMF and World Bank "my optimism was already big."

"And it surely hasn't become smaller," he added.

He did not detail how differences with the Greeks over their commitment to reforms -- especially on pensions -- and their need for debt relief would be resolved.

Still, Schaeuble said, "it is the common will of all three institutions, the EU commission, ECB (European Central Bank) and IMF to negotiate with the Greek government on the basis of a unified position."

"Everybody knows that the maneuvering space for the Greek government is limited," he said. "But all say at the same time Greece must do more and can do more."

Also in Washington, France's Finance Minister Michel Sapin said an agreement on Greece could come out of the Ecofin meeting in Amsterdam.

"It is crucial to resolve the Greek issue now or we will always be on the edge of a cliff," he told reporters.

"We have taken advantage of the presence in Washington of many political and financial leaders to move forward."