Washington -- While the world's top economies stressed their resolve to do everything it takes to solve the worst financial crisis since the Great Depression, the world's stock markets will have the final say on just how clear a message was delivered.

It was a weekend of heavy promises and calls for joint action. First, the world's seven leading economies -- those at the epicenter of the current financial turmoil -- on Friday vowed to use "all available tools" to stabilize their financial markets.

In a one-page statement, one of the shortest in recent memory, the Group of Seven offered five clear principles to shore up their banking sectors threatened with collapse.

They included a vow to prevent the failure of "systemically important" financial institutions and to use public funds to help banks raise enough capital to "re-establish confidence."

On Saturday, finance ministers from around the world offered their full backing. The International Monetary Fund's 185 members "strongly endorsed" the G-7's action plan.

The Group of 20 -- a wider bloc that includes budding economies China, India and Brazil -- lent their support and committed to using "all the economic and financial tools" of their own to keep the financial sector running smoothly.

IMF Managing Director Dominique Strauss-Kahn said the clear commitments would help unblock credit markets and predicted investors' reaction would be positive.

"In the coming days, what I expect is that the reaction by the different (financial) institutions will be positive enough to unfreeze the credit market and to restore the necessary funding," Strauss-Kahn said.

All countries have a stake. The IMF in its semi-annual economic survey Wednesday put the world on the brink of recession. Growth was forecast to slow to 3.9 percent this year and 3 percent in 2009. The IMF considers growth of under 3 percent a recession.

Global stocks have plummeted. Japan's Nikkei Index lost 24 percent last week and Germany's DAX more than one-fifth. On Wall Street, the Dow Jones Industrial Average lost 18 percent for its sharpest one-week point drop in history.

Meanwhile, finance ministers from developing countries, already dealing with food and fuel price surges, chronicled how exports were slowing and investment in their own countries was beginning to dry up. They urged wealth nations not to ease up on their aid commitments.

"We are now facing a world crisis," warned Brazilian Finance Minister Guido Mantega, who chairs the G-20.

But despite the agreements that joint action was needed, the statements this weekend were short on specifics.

The G-7 -- made up of the United States, Canada, Britain, France, Italy, Germany and Japan -- announced none of the new moves that some investors had been hoping for, such as a British plan to guarantee inter-bank lending.

"Unless the G-7, separately and jointly, act more decisively ... I'm afraid that next week could be quite difficult," wrote Simon Johnson, a former chief IMF economist, on his website baseline scenario.com.

European countries also held an emergency summit of eurogroup leaders in Paris Sunday to discuss possible solutions including the nationalization of troubled banks. Germany meanwhile is expected shortly to unveil its own rescue package to keep banks afloat.

As markets prepared to deliver their verdict, some finance ministers lamented what they viewed as unnecessary fear on the part of investors.

Mantegna called the markets "irrational." US Treasury Secretary Henry Paulson said investors were "naive" if they expected advanced economies to come up with the same set of policies for countries with wildly different financial, economic, political and legal systems.

Yet even the IMF's current chief economist sounded bleak: Olivier Blanchard told Italian daily Corriere della Sera that stocks may fall another 20 percent before bottoming out.

-- Chris Cermak /DPA/Expatica