The Japanese government is making final arrangements to inform the World Trade Organization of its readiness to take retaliatory steps against US tariff actions.
The US administration led by President Donald Trump last month chose not to exempt Japan from tariffs on steel and aluminum imports. The import duties were imposed in March on national security grounds.
Sources say the government will inform the WTO in line with international trade rules before the end of the week.
The government is considering imposing tariffs on US exports worth about 409 million dollars -- the equivalent of duties levied by the US through its tariffs.
It does not plan to specify the items subject to the tariffs.
Japan's stance differs from that of China and the European Union, which have responded to the US decision with reciprocal threats.
China has already imposed tariffs on US imports.
The Japanese government will likely continue to seek exemption from the US tariffs by hinting at the possibility of taking retaliatory action against the United States.