Japanese automaker Mitsubishi Motors on Wednesday admitted it falsified fuel economy test data for more than 6,00,000 vehicles. Tyre pressure figures were manipulated by its employees to compliment mileage rates, reported the BBC. The issue came to light after Nissan, with which Mitsubishi entered a joint venture to manufacture vehicles in 2011, highlighted inconsistencies in almost 4,70,00 cars. As many as 1,57,000 of Mitsubishi’s own light passenger cars and 4,68,000 vehicles produced for Nissan were involved in the inaccurate tests, the report said.

The matter was reported to the Transportation Ministry of Japan, Mitsubishi Motors President Tetsuro Aikawa said at a media briefing in Tokyo. Mitsubishi, Japan’s sixth-largest carmaker, said it has stopped making and selling the vehicles and had set up an independent panel to investigate the matter.

This follows the controversy surrounding German automaker Volkswagen, regarding the use of illegal emissions-control software in its cars in the United States. This is the first time a Japanese car manufacturer has reported such discrepancies in fuel efficiency figures. The company’s shares plunged more than 15% after the announcement was made, their largest one-day fall in nearly 12 years. It sold more than one million vehicles in 2015.