Trump steel tariff hike: Foreign nations express alarm
Foreign nations who export aluminium and steel to the US say they are considering retaliatory action after President Trump said he would introduce steep new tariffs on imports.
The European Union said it would "react firmly and commensurately to defend our interests", while Canada said it too would take "responsive measures".
Mr Trump said steel imports would face a 25% tariff, and aluminium 10%.
He has long complained the US was suffering from "unfair trade".
The US imports four times more steel than it exports, and is reliant on steel from more than 100 nations.
The value of shares in American steel manufacturers jumped significantly after the announcement of the tariff hike, which is expected to be signed off by Mr Trump next week.
But car-makers and other firms reliant on steel and aluminium saw the value of their shares fall.
'Unfair measures' - International reaction
Some of America's closest allies, including Canada and South Korea, are among the top five biggest sources of steel and aluminium for the US.
The EU was among the first to react to the news, with European Commission chief Jean-Claude Juncker saying: "We strongly regret this step, which appears to represent a blatant intervention to protect US domestic industry and not to be based on any national security justification."
He said they would consider World Trade Organization (WTO)-compatible counter-measures in the coming days. "We will not sit idly while our industry is hit with unfair measures that put thousands of European jobs at risk," he said.
His words were echoed by the German Steel Association which said the US move "clearly violates the rules of the World Trade Organization".
Canada's Foreign Affairs Minister Chrystia Freeland warned they also would "take responsive measures to defend its trade interests and workers".
She said Canada buys more American steel than any other country and "will continue to make this point directly with the American administration at all levels".
China is the 11th biggest exporter to the US, and the news is expected to provoke an angry reaction from Beijing - although Mr Trump's announcement came on the same day China's top trade official Lui He was in Washington for trade talks.
Reaction from inside the US
Mr Trump's announcement was in response to a recommendation by Secretary of Commerce Wilbur Ross, who said current levels of steel and aluminium imports "threatens to impair the national security".
But many industries that rely on steel use have lobbied against the tariffs as they fear increased costs if they have to use more US-made metals.
Members of the US oil and gas industry immediately urged Mr Trump to drop the plan.
Jack Gerard, president of the American Petroleum Institute, warned it would "undoubtedly raise costs for US businesses that rely heavily on steel and aluminium for the majority of their products - and ultimately consumers".
A spokeswoman for the Interstate Natural Gas Association of America told Reuters news agency that the type of steel needed for certain pipelines was not actually readily available domestically.
"We are urging the administration to avoid killing US jobs through a steel tariff that impacts pipelines," said Andy Black, CEO of the Association of Oil Pipe Lines (AOPL).
A spokesman for House of Representatives Speaker Paul Ryan, a leading Republican, said he hopes "the president will consider the unintended consequences of this idea and look at other approaches before moving forward".