GENEVA (Reuters) - Japan could lose $17 billion in car export potential in the U.S. following President Donald Trump's decision to introduce 25% tariffs on the automotive sector, the International Trade Centre said on Friday.

"Japan's automotive sector comprises 20% of the country's total exports and the majority of exports are headed to the U.S. market. Now the flat 25% tariff on the sector that came into force yesterday means that Japan could lose 17 billion in export potentials in the US, according to our calculations," Julia Spies, ITC chief of trade and market intelligence, told reporters in Geneva.