WASHINGTON - The Detroit Three automakers on Wednesday urged Congress to take action to stop efforts by Japan and South Korea to shore up their currencies, The Detroit News reported.

The automakers prodded Congress to "send a clear message to the governments of Japan and Korea: Do not intervene in currency markets."

It's the latest effort by the automakers to raise the issue of currency. It follows a meeting earlier this month with the senior auto adviser on currency issues.

The American Automotive Policy Council -- representing General Motors Co., Ford Motor Co. and Chrysler Group LLC, said both countries were engaging in "currency manipulation" that "unfairly boosts these nations' auto exports and hurts American jobs."

Automakers have complained for more than a decade that Japan and Korea haven't done enough to open their markets and allow their currency to move at market rates. A proposed Korea Free Trade agreement remains stalled in Congress -- largely because of concerns of midwestern Democrats that the deal doesn't do enough to open Korea's auto market.

The automakers cited Japan's decision last week to add another $56 billion to its special fund for currency interventions on top of the massive reserve already in place -- and Japan's Finance Minister Naoto Kan told the Japanese Diet last week that the government is ready to intervene in currency markets to depreciate the yen.

The group said Korea has been intervening repeatedly throughout 2009 and into 2010 to manipulate the value of its currency -- the won.

"We urge you to make clear to the governments of Japan and Korea that the U.S. Congress considers such interventions unacceptable and that any decision to proceed with or continue such interventionist policies will be strongly and directly challenged by the United States in defense of fairness and American jobs," the leaders said.

The group also sent a letter to the Japanese ambassador to the United States, Ichiro Fujisaki.

"American auto companies will consider intervention in foreign exchange rate markets by the Japanese government that weakens the yen as unfair competition directed at the American automotive market and American workers as the industry begins to recover from the economic recession," they wrote. "We will encourage our government to take strong and equivalent action in response to prevent harm to American jobs."

An official at the Japanese embassy who handles auto issues didn't immediately return a request seeking comment.

Korea and Japan remain the two most closed automotive markets, according to the Organization for Economic Co-Operation and Development -- which ranks the pair 29th and 30th of 30 total countries. Import penetration in both countries' auto market is less than 4.5 percent. They argue it's primarily because of non-tariff barriers like currency valuations.