US tariffs of 50 per cent on steel and aluminium will take effect from June 4 after Donald Trump signed an executive order on Tuesday escalating his global trade war.

U.S. President Donald Trump will sign an executive order on Tuesday making official his vow to double tariffs on steel and aluminum, White House spokeswoman Karoline Leavitt told reporters in a briefing.

President Donald Trump’s ambitious plan to broker dozens of trade deals with some of the United States’ closest trading partners has begun to show cracks as the clock on his 90-day pause for most country-specific tariffs winds down to just over one month.

The Trump administration is pressuring trade partners to make a deal as tariff threats loom. The U.S. trade representative's office recently sent letters to foreign countries telling them to make their best trade offers by Wednesday.