European officials said Tuesday that they plan to appeal for deeper involvement by the International Monetary Fund in addressing the region’s debt crisis, an acknowledgment that their efforts to date have fallen short.

With international investors continuing to press on weak links in the euro currency union, European finance ministers said they would turn to the IMF to help supplement their emergency bailout fund.

At the latest in a series of late-night meetings, the euro-zone ministers approved efforts to expand the financial effect of the existing bailout fund. But they recognized that it was unlikely to attract enough private investment to provide emergency financing to large countries such as Italy and Spain, which must raise hundreds of billions of dollars in coming months.

So the ministers said they would push for an increase in IMF funds available to euro-zone countries. The idea is to use the agency as a sort of conduit, allowing wealthier countries such as Germany, or perhaps the European Central Bank (ECB), to provide money that could then be directed back to Europe.

The fund would oversee how the money is used, ensuring that Italy or other possible beneficiaries adhere to specific targets for reducing government deficits or making economic changes.

The euro-zone nations “agree to rapidly explore an increase in the reserves of the IMF through the use of bilateral loans,” Jean-Claude Juncker, head of the finance ministers group, said at the end of Tuesday’s meeting in Brussels. Olli Rehn, head of European economic and monetary affairs, said discussions with the IMF were underway and that European nations could be tapped for loans to the agency.

Discussion of a deeper role for the IMF came as the ministers completed work on the design of the bailout fund, the European Financial Stability Facility, which was set up a year and a half ago to backstop euro-region governments that have trouble raising money on world bond markets. Funding for the bailout fund from the euro zone’s 17 nations has fallen short as larger countries, such as Italy, have run into trouble. Italy, the third-largest economy in the euro zone, has seen its borrowing costs spike and on Tuesday they remained at unsustainably high levels.

Efforts to double or triple the bailout fund’s firepower by attracting outside investors also have stumbled.

The IMF on its own would have difficulty underwriting a bailout of a major nation such as Italy. Meanwhile, the U.S. government and others have resisted any increase in IMF funding to be paid for by the agency’s 187 member nations. Bilateral loans to the IMF — for instance, those from individual countries — would skirt that problem and have been used before to boost IMF resources.

The IMF did not comment on the reports out of Brussels.

The finance ministers’ gathering on Tuesday kicked off a critical round of talks at a time when the options are narrowing for averting a default by one of the euro-zone countries and a breakup of the currency union.

The stakes are large. Other major economies, from the United States to China, are beginning to feel the drag from a developing downturn in the euro-zone economy. President Obama said this week that U.S. job growth could be dampened until Europe recovers. Emerging economies such as Poland are worried that their otherwise solid economic performance could be undone as banks in western Europe tighten the credit available to companies and pull back on foreign investments. The rising cost of borrowing for companies based in the euro zone is also threatening economic growth.

The finance ministers did clear one important hurdle: approving the latest loan installment to Greece so it could keep paying its bills. With a new government in Athens and the country’s opposition supporting the strict terms of an international bailout program, the IMF is expected to approve its share of the latest loan payment, as well. A new, multi-year program for Greece is being negotiated that entails banks and other private investors accepting a 50 percent loss in the value of Greek government bonds they hold.

But the Greek negotiations have become a virtual sideshow to the more fundamental questions European leaders are being pushed to answer. These include the proper role of the ECB and whether members of the currency union are prepared to enter into a deeper form of economic union.

Combined, the euro zone’s economy rivals that of the United States, while individual nations such as Italy have massive amounts of household wealth despite the high public debts. Marshaling those resources has proven difficult, however.

Global investors have become more skeptical about whether heavily indebted governments will honor their obligations. In its latest foray into world bond markets, Italy on Tuesday paid more than 7.3 percent on its benchmark 10-year note, five percentage points more than the rate paid by Germany — a striking example of how the fortunes of different euro-zone nations are diverging.

More evidence of Europe’s shaky foundation came at the ECB, where a weekly bond auction fell short. The bond sale was designed to offset the bank’s emergency purchases of government bonds, such as from Italy and Spain.

After nearly two years of trying to battle the crisis, European leaders say their focus has now turned toward an early December summit, where they will discuss a potentially profound reordering of Europe’s economic management that would transfer power over national budget decisions to a central authority.

“Our priority is to have the whole of the euro zone to be placed on a stronger treaty basis,” German Chancellor Angela Merkel said Tuesday. “This is what we have devoted all of our efforts to; this is what I’m concentrating on in all of the talks with my counterparts.”

Birnbaum reported from Berlin.