China and South Korea have vowed to defend their interests after the US imposed new tariffs on imported washing machines and solar panels.
The tariffs - of up to 50% - will affect the two Asian countries more than any other.
They are part of US President Donald Trump's "America First" trade policy, which aims to protect local manufacturers from foreign competition.
South Korea said it would complain to the World Trade Organization (WTO).
China, the world's biggest solar panel producer, said the move was an "overreaction" and pledged to "work with other WTO members to resolutely defend its legitimate interests".
India's Prime Minister Narendra Modi spoke against tariffs at the World Economic Forum in Davos in an apparent reference to the US measures, although India's own finance ministry is planning a 70% tariff on Chinese solar panels.