By Jeff Mason, Bart H. Meijer and David Brunnstrom WASHINGTON/BRUSSELS (Reuters) -U.S. President Donald Trump opened a new phase on Monday in the trade war he launched this year, telling partners, from powerhouse suppliers such as Japan and South Korea to minor players,

President Trump said Japan and South Korea would face tariffs of 25 percent unless they reached an agreement with the United States. Other countries received notice of higher levies.

President Donald Trump unveiled the first in a wave of promised letters that threaten to impose higher tariff rates on key trading partners, including levies of 25% on goods from Japan and South Korea,