SAN FRANCISCO (Reuters) - Two California lawyers filed a class action lawsuit on Tuesday against the Swiss National Bank charging the bank with laundering stolen Nazi gold and helping prolong World War Two.

The lawsuit in U.S. District Court in San Francisco was filed on behalf of more than 12 million non-Jewish civilian victims of the Nazis from the former Soviet Union and Yugoslavia.

It accuses the bank of exchanging hundreds of millions of dollars in looted gold and other assets from the Nazis between 1941 and 1945 -- providing Germany with the hard currency needed to buy supplies to keep fighting the war.

``This is an action against the Swiss National Bank and as yet unnamed Swiss recipients of loot from the Nazis and their allies,'' the suit filed by attorneys Tom Easton and Jonathan Levy said.

It is similar to a separate one that Easton and Levy previously filed against the Swiss National Bank, the Vatican Bank and Franciscan Order for allegedly laundering gold stolen from victims of Croatia's brutal Ustasha regime during the Second World War.

The lawsuit comes despite the fact that the Swiss central bank is covered by the $1.25 billion global settlement agreement reached in 1998 between Swiss banks and Jewish organizations aimed at settling the issue of looted World War Two assets. That deal was meant to shield banks from future class-action suits.

Representatives of the Swiss National Bank could not be reached for comment Tuesday, but have said in the past the bank is not under the jurisdiction of U.S. courts due to its status as a sovereign central bank.

Elan Steinberg, executive director of the World Jewish Congress said there was no question the Swiss National Bank received looted gold. But he added the position of the World Jewish Congress was that the global agreement offered legal closure to the Swiss National Bank.

``I think we have to retain the right for victims to sue,'' Steinberg said in an telephone interview. ``On the other hand, when a settlement is reached it should be respected.''

Levy, one of the lawyers who filed the lawsuit, argued the central bank waived its sovereignty by taking part in the global settlement and said the Nazi victims in his lawsuit were not included in the worldwide agreement.

``These particular victims were not compensated,'' Levy said in a telephone interview.

The lawsuit seeks restitution and an accounting of the looted assets. It alleges most of the stolen loot was sent to Berlin and deposited in the German State Bank and then exchanged through the Swiss National Bank and other Swiss banks.

This gave the Nazis the hard currency to buy vital war supplies from neutral countries and helped to lengthen the war, the lawsuit said.

``It didn't matter if it (loot) came from a Russian or a Jew, it was all treated the same way,'' Levy said. ``It went to the Reichsbank and then was exchanged with the Swiss National Bank for hard currency.''