The International Monetary Fund says the lingering Greek debt crisis poses a significant risk to the global economy.

An IMF statement Tuesday said markets around the world “remain unconvinced” that Europe's leaders will be able to rescue Greece from its mounting debt. It also warned that the crisis could spread, first to other European countries and then around the world.

European leaders are preparing to meet in Brussels Thursday to work on a second multi-billion-dollar bailout for Athens. The IMF and EU combined last year on a $160 billion package that so far has failed to bring any major improvements to the Greek economy.

German Chancellor Angela Merkel downplayed expectations for the summit, saying there will not be “one spectacular event” that solves everything. She told reporters in Hanover, Germany that any rescue will instead be a “controlled process.”

Investors have been growing increasingly concerned about Greece and several other debt-plagued European countries, including Spain and Italy.

The IMF statement urged European leaders to scale up its rescue fund and make it more flexible to help countries in trouble.

On Monday, Greek Finance Minister Evangelos Venizelos said a deal for another economic bailout for Greece is “attainable.”

Venizelos told the Associated Press that a deal can be reached in Brussels that would help avoid a “domino effect” in which Greece's problems would spread across the entire eurozone.

Venizelos also told the AP he believes Greece can have a budget surplus by next year.