Mitsubishi said it has gone back and re-tested the models from those model years sold in the U.S. market.

"Our findings confirm that fuel economy testing data for these U.S. market vehicles is accurate and complies with established EPA procedures," the company's North American unit said in a statement.

The U.S. Environmental Protection Agency said on Tuesday it ordered Mitsubishi to provide additional information and conduct new tests of U.S. vehicles after the Japanese automaker's admission that it did not properly follow fuel economy test procedures in Japan since 1991.

The EPA didn't immediately respond to a request for comment on Wednesday.

Mitsubishi said on Tuesday that it used fuel economy testing methods that did not comply with Japanese regulations for 25 years, much longer than previously known.

EPA spokeswoman Laura Allen said Tuesday the agency has instructed Mitsubishi to "provide additional information regarding their U.S. vehicles. The agency will be directing the company to conduct additional coast-down testing for vehicles sold in the U.S."

Shares in Mitsubishi, Japan's sixth-largest automaker, closed down almost 3 percent on Wednesday and have lost more than half their value since news of the scandal broke a week ago.

The company admitted to manipulating test data for four domestic mini-vehicle models, including two it produced for Nissan Motor Co.

The U.S. National Highway Traffic Safety Administration said last week it is also seeking information from Mitsubishi.

In 2015, Mitsubishi sold 95,342 vehicles in the United States, up 22.8 percent, accounting for 0.5 percent of U.S. auto industry sales, according to Autodata Corp. Mitsubishi U.S. sales are up 6 percent in the first three months of 2016.

(Reporting by David Shepardson in Washington; Editing by Bernard Orr and Alan Crosby)

By David Shepardson