Confusion over competing policy proposals reigned among officials and bankers on Monday as Europe struggled to put together a second bailout of Greece and prevent the region's debt crisis from spreading.

French government spokeswoman Valerie Pecresse said she believed a summit of the euro zone's 17 national leaders scheduled for Thursday in Brussels would agree on a rescue of Greece, supplementing a 110 billion euro ($154 billion) bailout launched in May last year.

But after three weeks of preparatory talks, it remained unclear whether government officials and commercial bankers could agree on a way for private owners of Greek government bonds -- banks, insurers and other investors -- to contribute to the bailout by taking cuts in the face value of their holdings.

The uncertainty pushed the euro down against other currencies on Monday and the government bond yields of indebted euro zone states rose, with Italy's 10-year yield climbing more than 0.2 percentage point to a euro-era high.

Paul de Grauwe, a professor of international economics at Leuven University in Belgium who has informally advised European Commission President Jose Manuel Barroso, said politicians had delayed taking decisive action on Greece for so long that their options were narrowing fast.

I'm afraid to hope. I still hope, yes, but I'm not optimistic, he said.

We've had solutions in the past, but we haven't grasped them. Now it's too late for some of those solutions to work anymore; the opportunity has been lost.

CANNOT RULE OUT ANYTHING

Officials are wrestling with a range of schemes for Europe's bailout fund, the European Financial Stability Facility, to finance a voluntary buy-back or swap of Greek debt that would be conducted at a discount to face value, helping to reduce Greece's 340 billion euro mountain of sovereign debt.

But all of the schemes could face major technical and legal obstacles, in some cases requiring the approval of national parliaments in the euro zone. Other proposals still appear to be on the table; Germany's Die Welt newspaper reported on Monday that governments were considering a levy on banks as a way to involve private creditors in rescuing Greece.

An official of a major euro zone government who is familiar with the talks said he had not heard of a proposal for a bank levy, but added: There are at the moment so many proposals that you cannot rule out anything.

If a deal on private creditor participation is reached, it may cut Greece's debt by just 20 or 30 billion euros, not nearly enough by itself to solve the problem. Analysts have estimated the debt would have to be roughly halved, to 80 percent of gross domestic product, to make it manageable in the long run.

German Chancellor Angela Merkel said on Sunday that while this week's summit was urgently necessary, she would only attend if lower-ranking officials had already prepared a clear rescue plan. I will only go there if there is a result.

BAILOUT

As part of the second bailout, officials have also been looking at other measures to help Greece including up to 60 billion euros of additional emergency loans from European governments and the International Monetary Fund; steps to recapitalize Greek and European banks; and ways to stimulate Greek economic growth.

Some official sources have said interest rates on bailout loans extended to Greece, Ireland and Portugal may be cut and maturities on those loans extended drastically, perhaps to 30 years.

There has also been talk of expanding the 750 billion euro bailout facility which the European Union and the IMF jointly created last year as the debt crisis erupted.

But de Grauwe said financial markets were now putting so much pressure on weak euro zone states that it was unclear whether cutting interest and extending maturities on their emergency loans would help them regain access to the markets.

If that was to be a solution, it's a solution we should have implemented months ago, when it would have worked.

Another source of concern is signs that the IMF and other major governments around the world, which want to prevent the European crisis from poisoning debt markets globally, may lose patience with Europe's handling of the problem.

Die Welt quoted unnamed diplomatic sources as saying the IMF was angered by Europe's crisis management and that influential parties in the Fund wished not to take part in further bailouts of Greece. It did not elaborate.

Former U.S. Treasury Secretary and White House adviser Lawrence Summers, writing in a column contributed to Reuters on Sunday, said Europe needed to act much more aggressively than it had done so far to prevent the Greek crisis from damaging both the region's single currency and the global economic recovery.

He recommended steps including sharp cuts in interest paid on bailout loans, allowing countries to buy European Union guarantees for their issues of new debt, and a menu of options for private investors to become involved.

It is to be hoped that European officials can engineer a decisive change in direction but if not, the world can no longer afford the deference that the IMF and non-European G20 officials have shown toward European policymakers over the last 15 months, Summers wrote.

Many private economists think some form of regional guarantee for countries' debt along the lines suggested by Summers -- or perhaps even the issuance of joint euro zone bonds -- may ultimately be the only way to emerge from the crisis without one or more weak states being forced out of the zone.

But Germany has shown no appetite for such a sweeping solution, which in any case would require a complex and time-consuming revision of the EU treaty.

We are against euro bonds, German government spokesman Steffen Seibert said on Friday, repeating Berlin's concern that a common bond for the single currency area would provide no meaningful incentives for national governments to pursue prudent budget policies.

(Writing by Andrew Torchia)