For all the attention European leaders are giving to possible long-term changes in the euro zone at their summit in Brussels this week, they still have an immediate financial crisis to confront. They will have to develop strategies to keep markets from swooning, banks from collapsing and one or more European governments from defaulting.

Those steps will center on several crucial questions: Will the International Monetary Fund get involved? How much more will the region’s wealthier governments contribute to keep their neighbors solvent? What more will the European Central Bank do?

A number of ideas have been floated for possible IMF involvement, including a plan that would use the agency as a conduit for some euro-zone governments to lend money to others. According to IMF and other officials, any such effort is unlikely to come together before a meeting in February of finance ministers from the world’s major economic powers.

Meanwhile, discussions have also focused on whether increased help from richer euro-zone nations could be a way to build a financial “firewall” around Italy, Spain and other nations considered most at risk.

One idea involves accelerating the creation of a new European bailout fund known as the European Stability Mechanism (ESM). It would be a $650 billion, permanent successor to the current temporary bailout fund, the European Financial Stability Facility (EFSF).

In 2013, the ESM is scheduled to take over the role of buying bonds issued by governments that are having trouble raising money at affordable rates. European officials say they may move the start date for the ESM to next year, and they are discussing whether to allow the EFSF to continue operating alongside it. Such a combined program would muster more than $1.2 trillion.

Some European leaders have suggested giving the ESM even more firepower by letting it borrow from the European Central Bank (ECB).

Officials in Germany, the leading contributor to the bailout funds, have been reluctant to make such changes in the ESM.

Many analysts think that the quickest and most effective help for Europe’s debt crisis will come from the ECB, whose governing board is scheduled to meet Thursday in Frankfurt.

At a minimum, the bank is expected to cut its benchmark interest rate. But ECB President Mario Draghi last week indicated that financial markets in Europe may need even more support as governments address their sovereign debt problems and try to rekindle growth in the 17-nation euro zone.

The ECB could provide longer-term loans to banks so they don’t have to scramble for short-term funding and could accept more types of collateral for loans so banks could borrow more if needed.

In a further sign of how tight banking markets have become in Europe, the ECB on Wednesday reported that banks were stashing more than $400 billion in its coffers — money that in better times would be flowing among financial firms and out to businesses and households.

The sovereign debt crisis in Europe has weighed heavily on the region’s banking sector, a traditionally heavy investor in government bonds. Standard & Poor’s on Wednesday said it may downgrade European banks on a blanket basis, given the continuing problems with government debt and an economy that is approaching recession.