Fears of a slowdown in the global economy pushed the dollar higher against most major currencies Tuesday.

The ICE U.S. Dollar Index, which measures the dollar against six other currencies, jumped to its highest level since Sept. 2010. Traders consider the dollar a safe haven asset, so it tends to rise when investors are worried about the economy.

On Tuesday the Fitch ratings agency downgraded Japan's credit rating, citing the country's ballooning government debt.

Continuing political and financial uncertainty in Greece pushed shares on the Athens Stock Exchange down to their lowest level in 22 years. Also, the Organization for Economic Cooperation and Development warned that the 17 countries that use the euro risk falling into a "severe recession." The group called on governments and Europe's central bank to act quickly to keep the slowdown from dragging down the global economy.

The euro fell to $1.2756 from $1.2793. The British pound fell to $1.5799 from $1.5807.

The dollar rose to 79.92 Japanese yen from 79.36 yen, to 0.9419 Swiss franc from 0.9391 Swiss franc and to 1.0182 Canadian dollar from 1.0190 Canadian dollar.