Underscoring the gravity of the situation, President Bush convened an early morning meeting at the White House on Saturday with finance ministers from the Group of 7 industrialized countries.

“All of us recognize that this is a serious global crisis, and therefore requires a serious global response, for the good of our people,” Mr. Bush said afterward in the Rose Garden, flanked by the ministers, who are in Washington for the annual meetings of the International Monetary Fund and the World Bank.

Mr. Bush said the countries had agreed to general principles to respond to the crisis, including working to prevent the collapse of important financial institutions and protecting the deposits of savers. But he offered no details on other measures, suggesting that there were still differences among countries about which steps to take to shore up their respective financial systems.

To some extent, the effort to agree on a coordinated plan is being driven less by the hope that such measures will carry more punch than by the fear that nations acting alone could destabilize the system.

Those worries grew in recent days when Iceland seized its three major banks, which were failing, and appeared to guarantee the deposits of Icelanders over those of foreigners. That provoked a fierce reaction from Britain, which is now in talks with Iceland to get back the deposits of British citizens.

With the United States and Europe working together on ways to secure their banking systems, economists are concerned that money may flow out of other countries, particularly emerging markets, to Western countries if investors decide that those markets are not as safe.

The United States sought to reassure these countries in a meeting on Saturday evening of the Group of 20, which includes countries with large emerging markets, like China and Russia.