Major Asian nations reacted sharply to U.S. President Donald Trump's decision to impose tariffs on steel and aluminum imports on Friday, warning of damage to close relations amid industry calls for retaliation.
Japan said the move would have a "big impact" on the countries' close bilateral ties, while China said it was "resolutely opposed" to the decision and South Korea said it may file a complaint to the World Trade Organization.
Trump on Thursday pressed ahead with the imposition of 25 percent tariffs on steel imports and 10 percent for aluminium on Thursday, though he announced exemptions for Canada and Mexico, and said exceptions could also be made for other allies.
China, which produces half the world's steel, will assess any damage caused by the U.S. move and "firmly defend its legitimate rights and interests," the country's Ministry of Commerce said.
The tariffs would "seriously impact the normal order of international trade," China's commerce ministry said.
The United States' decision to impose tariffs on steel and aluminium was "regrettable", Japanese Foreign Minister Taro Kono said in a statement on Friday.
Japan also said on Friday that Japan would continue to ask the United States to exempt it from Washington's plan to impose tariffs on imports of steel and aluminium.
Trade tensions between China and United States have risen since Trump took office. China accounts for only a small fraction of U.S. steel imports, but its massive industrial expansion has helped create a global glut of steel that has driven down prices.
China's steel and metals associations urged the government to retaliate against the United States, citing imports ranging from stainless steel to coal, agricultural products and electronics.
"The cost of a trade war will be tremendous and it will make everyone unhappy," Junichi Makino, chief economist at SMBC Nikko Securities in Tokyo, said in a report on Friday.
Trump's declaration coincided with the signing by 11 countries of a new Trans-Pacific trade pact that the United States withdrew from last year. South Korea and Australia both said they would seek exceptions.
The European Union, Brazil and Argentina said overnight they should not be targeted or would seek exemptions.
Shares in China's steel and aluminium makers fell on Friday morning. Baoshan Iron & Steel was down around 3 percent, while Hesteel and Beijing Shougang were down less than 1 percent.
In South Korea, shares in Posco were down more than 2 percent, while in Tokyo, Japan's biggest steelmaker Nippon Steel & Sumitomo Metal was up slightly.