Shares in U.S. steelmakers rose in premarket U.S. trading on Monday after President Donald Trump announced plans to slap 25% tariffs on steel and aluminum imports.

Pennsylvania-based U.S. Steel and steel producer Cleveland-Cliffs (NYSE:CLF) both jumped prior to the opening bell on Wall Street. North Carolina-headquartered Nucor (NYSE:NUE) and Indiana-based Steel Dynamics (NASDAQ:STLD) also gained.

Meanwhile, shares in European counterparts like ArcelorMittal SA (AS:MT) (NYSE:MT) and Voestalpine AG (VIE:VOES) dipped in early trading, with analysts at Morgan Stanley (NYSE:MS) flagging that the tariffs may push up costs for exporters to the U.S. ArcelorMittal’s earnings are “likely to be negatively impacted” in particular, the analysts added.

“Yet, the rapidly evolving policy environment suggests more changes are likely,” the analysts wrote in a note to clients.

Speaking to reporters on Air Force One on Sunday, Trump said he will announce the levies on Monday, followed by the reciprocal tariffs on many countries on Tuesday or Wednesday, with both duties to be effective immediately.

Trump’s tariff threat comes just days after his 10% duties against China took effect, with some analysts suggesting he may adopting a tougher trade policy to help push through his broader international agenda. Beijing later retaliated with a slew of its own levies.

The president also said he would impose 25% tariffs against Canada and Mexico last week, but postponed the moves after he received assurances from the two countries around tightening border security.

Canada, Brazil, Mexico, South Korea, and Vietnam are the biggest exporters of steel to the U.S., government data showed. Canada is also by far the biggest exporter of aluminum to the U.S.

In his first term, Trump imposed 25% tariffs on steel and 10% tariffs on aluminum, but subsequently granted duty-free quotas to allies such as Canada, Mexico, and Brazil.

Cleveland-Cliffs CEO Lourenco Goncalves has previously argued that the tariffs could have a “long-term positive impact” that will help bolster America’s manufacturing sector. Goncalves echoed Trump’s statement that the U.S. was being “taken advantage of” by its international trading partners.

Analysts have predicted that U.S. steel mills could also use the tariffs to receive higher prices from buyers keen on locking in orders before the tariffs come into effect.