TOKYO — Mitsubishi Motors on Friday posted a surprise operating loss in the third quarter, its worst quarterly performance in more than three years, hurt by falling sales in China, Japan and Southeast Asia, as well as a stronger yen. The carmaker posted an operating loss of 6.6 billion yen ($60.2 million) for the October-December quarter, widely missing an average forecast for a profit of 11.6 billion yen, based on analyst estimates compiled by Refinitiv. It was the firm's biggest loss since the July-September 2016 quarter, when a mileage cheating scandal sapped profits. However, Mitsubishi stuck to an earlier forecast for a 73% drop in full-year operating profit to 30 billion yen in the fiscal year ending in March. The automaker's net loss for the quarter just ended came in at 14.4 billion yen. The fall in quarterly sales was worst in China and at home, while sales also slipped in ASEAN countries, traditionally a stronghold, leading to a 16% fall in global vehicle sales to 320,000 units. The automaker also said it would keep some of its offices in China closed through Feb. 9, as a new coronavirus spreads throughout the country and beyond. The automaking alliance of Mitsubishi, Renault and Nissan on Thursday said they had "no other option" but to drastically improve their joint operations to remain competitive in the fast-changing global auto industry.