Greece's finance minister on Sunday told the International Monetary Fund chief that his country will repay a substantial loan from the organization that is due this week.

IMF Managing Director Christine Lagarde and Yanis Varoufakis met in Washington for an "informal discussion" on the debt-stricken nation's reform program, an IMF statement said. The Greek government has said Varoufakis will meet with U.S. Treasury officials Monday.

Greece is in difficult negotiations with creditors over its bailout program, which has delayed the disbursement of the final 7.2 billion euro ($7.9 billion) aid tranche. That has led to a cash crunch, forcing the government to tap reserves.

Athens has been hoping for at least a partial release of the final bailout installment in order to avoid default and to pay salaries and pensions.

"We both agreed that effective cooperation is in everyone's interest," Lagarde said in the statement. "We noted that continuing uncertainty is not in Greece's interest."

Greece must repay a 450 million euro IMF loan installment on Thursday. Deputy finance minister Dimitris Mardas on Saturday told TV station Mega that Greece has the funds but it is up to the government to decide whether to pay.

Greece and its creditors have been negotiating which reforms it should enact to its economy to receive more funding.

Lagarde said discussions resume "promptly" on Monday between technical teams and authorities in Athens and in Brussels.

Since 2010, Greece has been dependent on rescue loans worth 240 billion euros from other eurozone countries and the IMF. Prime Minister Alexis Tsipras was elected in January on promises to abolish the deeply resented bailout conditions, which included deep spending cuts and tax hikes.

However, the new Syriza government has since softened many pre-election promises.