The European Commission, which coordinates trade policy for the 28-nation EU, the world's biggest trading bloc, has said it is ready to impose safeguards, tariffs or quotas to protect its own steel and aluminium industries from products diverted to Europe because of the USA measures.
European trade commissioner Cecilia Malmstrom met U.S. trade envoy Robert Lighthizer in Brussels on Saturday for what she described as "frank" discussions which "brought no immediate clarity".
In talks, the United States should not expect any European Union concessions to win an exemption, European Union officials said.
Canada and Mexico will be exempt from the tariffs initially, and Australia is optimistic that it too will gain exemption.
The EU is also maintaining a threat of counter-measures that would target USA imports ranging from maize to motorcycles, and may publish its list next week to allow industry and other interested parties to give their input.
Trump set import tariffs on Thursday of 25 percent on steel and 10 percent on aluminium.
Malmstroem said the real problem is an oversupply of steel on global markets, and she rejected Trump's assertion that the tariffs are needed to protect USA national security, especially when most European Union countries are members of North Atlantic Treaty Organisation.
She said discussions would continue next week.
"We expressed our concern". Hiroshige Seko told a news conference Mr Lighthizer had only explained the schedule and procedure of the United States actions in talks in Brussels.
Seko did not go into what conditions might allow Japan to evade tariffs and, asked if Lighthizer had brought up the US trade deficit with Japan, Seko said no.
The two also met with Japan's Minister of Economy, Trade and Industry of Japan Hiroshige Seko, and all three pledged in a statement afterward to work together to fight dumping that hurts jobs and industries around the world.
Germany - singled out for particular criticism by Trump - accused Washington of protectionism, calling the tariffs an "affront to close partners".
The European steel association Eurofer in Brussels today warned the US President's new import tariffs were "harmful and counterproductive" and could lead to the loss of tens of thousands of jobs in Europe. "Now we are talking about unilateral action against worldwide rules, and we want to sort it out before it really becomes a problem".
"We're not looking for a trade war", Ross said. "It could disrupt the steel and aluminium markets of the world and have a negative impact", Mr Seko told reporters after meeting Mr Lighthizer to seek an exemption for Japanese producers.
European Commission Vice-President Jyrki Katainen told AFP on Friday the bloc could form a "coalition of like-minded countries" to file a complaint at the WTO, though this procedure usually takes around two years.