The International Monetary Fund said Thursday it had reached a staff-level agreement to support bankrupt Sri Lanka with a $2.9 billion bailout spread over four years.

Financial assistance from the international lender of last resort is conditional on a plan to restructure the island nation's $51 billion foreign debt after an April default.

"The objectives of Sri Lanka's new Fund-supported program are to restore macroeconomic stability and debt sustainability," the IMF said in a statement after nine days of talks in Colombo.

"Debt relief from Sri Lanka's creditors and additional financing from multilateral partners will be required to help ensure debt sustainability and close financing gaps," the statement added.

"Financing assurances to restore debt sustainability from Sri Lanka's official creditors and making a good faith effort to reach a collaborative agreement with private creditors are crucial before the IMF can provide financial support."

The IMF said Sri Lanka had agreed to increase revenue, remove subsidies, ensure a flexible exchange rate and rebuild its foreign reserves, which had hit rock bottom.

Sri Lanka's unprecedented economic crisis sparked street protests that led to the ouster of then-president Gotabaya Rajapaksa in July.

The nation of 22 million has been enduring shortages of food, fuel and medicine while facing lengthy power cuts and galloping inflation since late last year.