After months of silence, the banks said they would reject "unfounded and excessive" demands for more. They said in a statement that the World Jewish Congress (WJC) and lawyers for Holocaust victims suing the banks were putting U.S.-brokered negotiations at risk.
The WJC condemned the banks for going public with their offer despite a U.S. court's gag order. The talks, which were scheduled to resume in Washington on Tuesday, remained up in the air on Friday.
The announcement by Credit Suisse, Swiss Bank Corp. and Union Bank of Switzerland marked the first time the banks have specified a figure for a possible settlement.
The $600 million, they said, would include $70 million already paid into a fund to help needy Holocaust survivors.
"By all legitimate criteria, this is a fair offer," the banks said in their joint statement.
Initial reaction from other Jewish groups, which have estimated the banks still hold billions of dollars in dormant wartime accounts, was also critical.
"The Swiss banks know that the amounts they are discussing are offensive, and if we were not dealing with such a tragic story, this would be laughable," Yoram Dori, an Israeli spokesman for the World Jewish Restitution Organization said.
The New York-based group tries to ensure that property and money lost or looted during World War II is returned to Jews.
The three Swiss banks urged the plaintiffs to accept the offer "so that money can immediately be distributed to Holocaust survivors and heirs of Holocaust victims."
"The purpose of this statement is, at this important juncture of the negotiations for settling the class-action suits, to state the facts, because there has been so much speculation, so many leads and semi-leaks," CS Group Chairman Rainer Gut said.
Credit Suisse, Swiss Bank Corp. and Union Bank of Switzerland are negotiating with Jewish organizations and lawyers for class-action claimants on a settlement.
They met June 5 with lawyers for Holocaust survivors amid reports the banks would offer more than $1 billion to settle claims they stole assets from dormant wartime accounts. Edward Fagan, an attorney for the plaintiffs, had said $1 billion might not satisfy some claimants.
Tens of thousands of Holocaust victims deposited money in Swiss banks when the Nazis were gaining power in Europe.
Plaintiffs, however, say bank officials stonewalled survivors and their heirs after World War II, claiming they could not find accounts or demanding nonexistent death certificates before giving funds to relatives of those who died in concentration camps.