Investing.com-- U.S. President Donald Trump said on Sunday that he will announce additional 25% tariffs on all steel and aluminum imports into the U.S., and will also announce reciprocal duties over what he sees as unfair trading practices. 

Speaking to reporters on Air Force One, Trump said he will announce the 25% tariffs on Monday, and will announce the reciprocal tariffs on Tuesday or Wednesday, with both duties to be effective immediately. 

The president was on his way to the NFL Super Bowl in New Orleans- a route that saw him fly over the Gulf of America, which the president had recently renamed from the Gulf of Mexico. 

Trump on Sunday also signed an executive order recognizing February 9 as “Gulf of America Day.” 

Trump’s tariff threat comes just days after his 10% duties against China took effect, as the U.S. president uses tougher trade policy to push through his broader international agenda. Beijing had retaliated with a slew of measures and duties.

He had threatened 25% tariffs against Canada and Mexico over stricter border control, but had postponed the tariffs on assurances from the two countries. 

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.

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

On reciprocal tariffs, Trump said he will hold a conference later this week to provide more information on reciprocal trade tariffs- plans for which he had first revealed on Friday. 

The president has consistently criticized uneven import duties imposed by other countries on U.S. goods. He has long criticized the European Union’s 10% tariffs on U.S. auto imports, which is much higher than the 2.5% import duty charged by the U.S.

Analysts and Federal Reserve officials have expressed some concerns that Trump’s trade tariffs- which will be borne by U.S. importers, will push up inflation in the coming months.

U.S. stock index futures crept lower after Trump’s announcement.