Inside safe deposit boxes at Riggs Bank is more than $710 million in cashier's checks that Riggs doesn't want. Neither does any other bank.

The stash, once in checking accounts held by the embassies of Saudi Arabia and Equatorial Guinea, is likely to grow. After being fined $25 million for violating anti-money-laundering laws in its embassy banking division, Riggs has asked more than 100 embassy clients to find other banking arrangements by mid-July, according to sources familiar with the matter who spoke on condition they not be identified.

But the business, in the words of one area banker who has refused to accept it, is proving "toxic." The embassy of Saudi Arabia, a key focus of the regulatory probes at Riggs, and a number of African and South American countries are having so much trouble finding a new bank that the State Department has asked banking regulators to step in.

"The embassy has been meeting its payroll requirements and paying salaries but in the long run, the embassy cannot function as an embassy if we don't have a local bank," said Nael Jubeir, a spokesman for the Saudi Embassy.

While a spokesman at the State Department referred questions to the Treasury Department, a top Treasury official confirmed that State officials have asked Treasury officials to ascertain whether banks are unnecessarily denying services to the embassies.

"As Riggs has gone about terminating these embassy relationships, the embassies in turn went to the State Department," said William J. Fox, director of the Financial Crimes Enforcement Network, the Treasury division that coordinates anti-money-laundering enforcement efforts. "Some of these countries have gone out to find other [banks], and I think they are apparently having difficulty. Some are being banked, others are having difficulty."

Fox and other banking regulators called a meeting in New York on Tuesday with a group of banks, including Citibank, BB&T, SunTrust, Bank of America, J.P. Morgan Chase and Wachovia. News of the meeting was reported Tuesday night by Moneylaundering.com, an online trade journal, and yesterday by the New York Times.

The purpose of the meeting, Fox said, was to educate other banks about the reasons Riggs's embassy business ran afoul of anti-money-laundering laws, not to persuade banks to take on the embassy business. Fox and the banks also discussed specific areas of risk associated with embassy banking.

Of Riggs's $4.2 billion in deposits at the end of 2003, $1 billion, or 23 percent, was in embassy banking. But the business provided much more prestige than profit for Riggs over the years, and other bankers now say the financial rewards from embassy business aren't worth the regulatory scrutiny and the difficulties associated with monitoring the accounts for potential illegal activity.

Riggs was fined for not following proper anti-money-laundering procedures in its embassy banking business, and failing to file "suspicious activity reports" to regulators on more than two dozen large and unusual transactions conducted by the Saudi ambassador, Prince Bandar bin Sultan, and other officials at the Saudi and Equatorial Guinean embassies going back to 2001.

Federal investigators have been looking at the Saudi accounts for evidence of money laundering but have reached no conclusions about the reasons for the transactions. Saudi Arabian and bank officials have said none of the transactions in question were in themselves illegal, only that the bank did not file proper paperwork.

"Banks are being penalized for what they failed to do and in turn the customers are being punished," Jubeir said. "Riggs failed to report to the regulators and to file certain forms. . . . We have done nothing illegal."

A source familiar with the matter, who spoke on the condition that he not be identified, said the Saudi Embassy, Bandar and several other governmental entities and related individuals have more than $10 million in cashier's checks waiting for them in a Riggs safe deposit box. Riggs has said it ended its business relationship with the Saudis in March, though the Saudis say they initiated the termination of the accounts.

Officials at Equatorial Guinea's embassy could not be reached, but a source close to the embassy, who spoke on the condition that he not be identified, said the embassy has been turned away by four banks in the Washington area since Riggs ended its relationship in February. The embassy two weeks ago found a bank, which the source declined to name, but only for the embassy's operating account -- which uses government money to pay the ordinary expenses of running the embassy.

The country's treasury account, with about $701 million, was closed by Riggs but the funds remain in a safe deposit box at the bank. The source said the country was in the process of arranging a transfer of the money to a non-U.S. bank.

The money in the treasury account comes principally from Exxon Mobil Corp., which pays Equatorial Guinea $300 million to $400 million a year as part of an oil extraction contract. Equatorial Guinea has no domestic banks capable of handling such large amounts, so Riggs acted as the country's central bank.

Mark Hendrix, a Riggs spokesman, said he couldn't comment on individual customer relationships past or present, but said the bank is winding down its embassy business. "As we publicly stated on April 29, there were certain embassy businesses that we were exiting that did not meet a strict risk criteria adopted by our board and management," Hendrix said.