By Sakari Suoninen and Sarah Marsh
FRANKFURT/BERLIN (Reuters) - The European Central Bank faced pressure on Thursday to take steps to contain the euro zone debt crisis and prevent it affecting the United States and Asia, but was unlikely to announce mass new bond purchases.
Pressure has grown on the ECB to act since last weekend's 85 billion-euro ($110.7-billion) EU-IMF rescue of Ireland failed to dispel fears that other countries using the euro, such as Portugal or Spain, could require a bailout.
Suggestions that the ECB could rush through new anti-crisis measures, such as expanding its government bond buying, helped the euro stabilize and lifted stock markets.
A Spanish government source said EU leaders could hold a summit in the near future to show unity in the face of intense market pressure on the euro zone but a meeting depended on the actions of the ECB.
"If the signal from the ECB was insufficient, the need for a meeting of leaders rises. The outcome of the ECB meeting can change things," a government source said.
German Economy Minister Rainer Bruederle said extra liquidity alone would not resolve Europe's debt problems and described the last U.S. fiscal stimulus package as excessive.
"Permanently printing money is not the solution," German Economy Minister Bruederle said. "The money presses must not fall into the hands of politicians."
But the ECB could disappoint investors if it decides at its monthly meeting only to continue its current course of action -- keeping its liquidity taps for euro zone banks wide open -- and does no more than hint at more government bond purchases.
"The price action ... adds to risk that the market may be disappointed with today's outcome," Citigroup currency and markets strategists said.
International Monetary Fund chief Dominique Strauss-Kahn, visiting India, said the situation in Europe was "serious" and the IMF was ready to provide financial and technical support to member states if needed.
But Spanish Prime Minister Jose Luis Rodriguez Zapatero said Madrid would not need to tap any European Union funds to help it through its debt problems.
Germany's Bruederle also said there was a good chance neither Lisbon nor Madrid would need a rescue.
But even Germany, the euro zone's biggest economy, struggled to sell its bonds on Wednesday and Portugal's borrowing costs soared.
ALL EYES ON ECB
Markets are waiting to see how ECB President Jean-Claude Trichet will respond when he addresses media at 1330 GMT on Thursday.
Some investors hope the ECB will ramp up its government bond buying program, launched in May after Greece was bailed out. But others expect no more than hints in that direction, saying it is too soon for any conclusive announcement given a fierce debate within the ECB about the merits of such action.
Bundesbank head Axel Weber has called for the program to be scrapped and fellow ECB members have criticized the U.S. Federal Reserve's decision to buy $600 billion of U.S. debt.
In Washington, the White House said President Barack Obama was briefed regularly on developments in Europe, while a senior Treasury official was heading to Berlin for talks on the economic situation after meetings on Wednesday in Madrid.
"It's important to the global economy and to our economic recovery," said White House spokesman Robert Gibbs. A senior G20 source in Asia also told Reuters that deputy finance ministers discussed the situation on Monday..
A U.S. official told Reuters that Washington would support boosting an EU rescue facility via IMF funds, news that bolstered the euro, helping it stabilize around $1.3130.
"It is up to the Europeans," the U.S. official said. "We will certainly support using the IMF in these circumstances."
However, a Treasury Department spokesman later said: "an extra commitment is not something we're discussing right now.." A Japanese government official also said Tokyo believed the IMF had sufficient funds now to deal with the European crisis.
CALLS TO TEAR UP RULE BOOK
Economists have urged the ECB to tear up its rule book and do all it can to protect the euro, particularly since governments seem to be running out of ideas how to restore confidence in their monetary union.
Markets in Asia followed with Japan's Nikkei scaling a five-month high and markets elsewhere in Asia-Pacific climbing 1.3 percent.
But debt auctions in Portugal and Germany on Wednesday showed investors remain nervous. Lisbon's borrowing costs surged in a 12-month bill auction and a German five-year note sale drew the weakest demand in half a year.
Euro zone officials have admonished markets for doubting the currency bloc's ability to solve its problems but, with no unity among European governments about what to do, radical ECB action is among the few options left.
Germany has resisted pressure from France and others to turn the euro zone into a "fiscal union," a step that could help the bloc address its economic imbalances but require members to sacrifice sovereignty for the good of the group.
Zapatero called on Thursday for a "much more integrated fiscal policy" for the euro zone. Portuguese Treasury Secretary Carlos Pina said the EU should "deepen its budget and create a European Treasury" to defend the euro, a move that would be anathema to Berlin.
Chancellor Angela Merkel is also reluctant to top up EU's bailout funds at the expense of German taxpayers, while Berlin's partners are clamoring for more.
(Writing by Timothy Heritage and Tomasz Janowski; Editing by Jon Boyle)