WASHINGTON  President Obama will face significant challenges at a summit meeting in Toronto next week, where he will be trying to secure cooperation from European and Chinese leaders in nurturing the still-fragile recovery of the global economy.

European countries are pulling back on spending with a speed that the Obama administration believes could derail the global recovery. China signaled this week that it would not let its currency rise in value anytime soon, raising the prospect of a showdown with Congress. Germany and France have turned skittish about an American-led push to raise capital and liquidity requirements for large banks.

Meanwhile, the United States and Britain favor a tax on the giant banks, but do not support a further-reaching proposal by the European Union to tax financial transactions. Canada, Japan and Australia oppose any form of bank tax.

The disagreements threaten to hurt the effectiveness of the Group of 20, the expanded club of nations that Mr. Obama and his predecessor, George W. Bush, have used to coordinate the response to the financial crisis.