WASHINGTON, Dec. 21 (Xinhua) -- The U.S. Federal Reserve announced on Tuesday that it had authorized an extension of its temporary U.S. dollar liquidity swap arrangements with the Bank of Canada, the Bank of England, the European Central Bank, the Bank of Japan and the Swiss National Bank.

The swap arrangements, established in May 2010, had been previously authorized through January 2011. The Fed announced on Tuesday to extend them through Aug. 1, 2011, the U.S. central bank said in a short statement.

The swap facilities aimed at responding to the re-emergence of strains in short term funding markets in Europe due to the sovereign debt crisis.

They were designed to improve liquidity conditions in global money markets and to minimize the risk that strains abroad could spread to U.S. markets, by providing foreign central banks with the capacity to deliver U.S. dollar funding to institutions in their jurisdictions.