WASHINGTON >> The United States and Europe are considering unprecedented punishment against Iran that could immediately cripple the country’s financial lifeline. But it’s an extreme option in the banking world that would come with its own costs.

The Obama administration wants Iran evicted from SWIFT, an independent financial clearinghouse that is crucial to the country’s overseas oil sales. That would leapfrog the current slow-pressure campaign of sanctions aimed at persuading Iran to drop what the U.S. and its allies contend is a drive toward developing and building nuclear weapons. It also perhaps would buy time for the U.S. to persuade Israel not to launch a pre-emptive military strike on Iran this spring.

The last-resort financial effort suggests the U.S. and Europe are grasping for ways to show immediate results because economic sanctions have so far failed to force Iran back to nuclear talks

But such a penalty could send oil prices soaring when many of the world’s economies are still frail. It also could hurt ordinary Iranians and undercut the reputation of SWIFT, a banking hub used by virtually every nation and corporation around the world. The organization’s full name is the Society for Worldwide Interbank Financial Telecommunications.

Meanwhile, violence is increasing. Explosions in Bangkok on Tuesday — Israel’s defense minister labeled them an "attempted terrorist attack" — came the day after Israel accused Iran of trying to kill its diplomats in India and Georgia. Those attacks followed the recent killings of Iranian scientists.

In the financial world, the United States can’t order SWIFT to kick Iran out. But it has leverage in that it can punish the Brussels-based organization’s board of directors individually, possibly freezing their assets or limiting their travel. Talks are focused now on having Europe make the first move.

Short of total expulsion, Washington and representatives of several European nations are in talks over ways to restrict Iran’s use of the banking consortium to collect oil profits.

The Obama administration is divided over whether the possible gain is worth the risk in trying to threaten SWIFT into kicking out a member country, in part because of concern that it would set back the global financial recovery. Iran remains a global financial player despite years of banking sanctions, and blocking it from using the respected transfer system would be a black mark like no other.

More than 40 Iranian banks and institutions use SWIFT to process financial transactions, and losing access to that flow of international funds could badly damage the Islamic republic’s economy. It would also probably hurt average Iranians more than the welter of existing banking sanctions already in place since prices for household goods would rise while the value of Iranian currency would drop.

Lawyers for SWIFT are holding meetings in Washington. People familiar with the talks say a compromise is possible in which SWIFT would voluntarily bar or restrict Iranian transfers.

But if SWIFT fails to act on its own, the U.S. expects Europe to require it to terminate services for Iranian banks, one Obama administration official said.

David Cohen, the Treasury Department’s undersecretary for terrorism and financial intelligence, delivered that message to European Union officials in Brussels earlier this month, said the official, who was not authorized to speak publicly and thus spoke only on the condition of anonymity.

Mark Dubowitz, a sanctions expert advising the White House on Iran, said the Obama administration is having detailed discussions on the merits and consequences of forcing SWIFT to block Iranian transactions.

Some in the administration also prefer to give time for new sanctions on Iran’s Central Bank, officially enforced starting just this month, to take hold before layering on a round of even more draconian penalties.

SWIFT was involved in a separate controversy when it was revealed in 2006 that it had skirted the EU’s strict privacy laws after the Sept. 11, 2001, attacks by transferring millions of pieces of personal information from its U.S. offices to American authorities as part of the US Terrorist Finance Tracking Program.

"It is an essential cog in the wheel, if not the wheel itself, in international financial transactions and trade," said David Aufhauser, former general counsel at the Treasury Department who worked with SWIFT to set up that information transfer.

SWIFT handles cross-border payments for more than 10,000 financial institutions and corporations in 210 countries. It lets users exchange financial information securely and reliably, thereby lowering costs and reducing risk. It operates on trust and neutrality — SWIFT accepts nearly all comers and does not judge the merits of the transactions passing through its secure message system. Its managers generally brush off investigators and enforcement agencies, telling them to take up suspected wrongdoing directly with nations or corporations.

Established in 1973, the essential but little-known hub is overseen by major central banks, including the U.S. Federal Reserve and the European Central Bank.

Lawyers familiar with SWIFT’s operations said it could bar processing actions with any Iranian party or third parties representing Iran, though that would open the consortium to complaints of favoritism or political influence. It could permit the processing but quarantine Iranian transactions, or require warnings to those doing business with Iran. Penalties on Iran short of expulsion could allow SWIFT to preserve a greater appearance of neutrality but make business partners think twice, lawyers said.

Proponents of blocking Iran from SWIFT say the financial network’s own bylaws require that its services not be used to facilitate illegal activities and allow it to prohibit users that are subject to sanctions.

While the U.S. and Europe debate options, some American lawmakers are trying to increase pressure on SWIFT. The Senate Banking Committee passed a measure earlier this month directing the White House to press SWIFT to block Iranian entities.

Rep. Ileana Ros-Lehtinen, chairwoman of the House Foreign Affairs Committee, also introduced a tougher bill that would compel the administration to sanction SWIFT unless it stopped providing services to Iran.

If lawmakers were to pass a compromise bill, final legislation could land on the president’s desk in late spring or early summer, according to a senior Senate aide.

The pending legislation has caught the attention of officials at SWIFT. The financial network’s general counsel and other advisers requested a meeting with congressional lawmakers and staff, the aide said.

Those meetings are scheduled in Washington for the week of Feb. 20, said the aide, who also spoke only on condition of anonymity.

Officials close to the White House say the Obama administration is comfortable with the less restrictive language in the Senate Banking Committee measure, but has concerns that more-binding legislation would leave the U.S. less flexibility in dealing with Iran.

SWIFT did not respond to requests for comment. In a brief statement posted on its website, the consortium said it is committed to fighting misuse of the financial system to finance terrorism and has cooperated with enforcement agencies in the U.S. and Europe.

Without addressing the specifics of a full expulsion or more limited block on Iranian transactions, SWIFT’s statement urged caution.

"SWIFT remains committed to maintaining its role as a neutral global financial communications network" while complying with sanctions laws, the statement said.

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Associated Press writer Slobodan Lekic contributed to this story from Brussels.