US president-elect Donald Trump has pledged to introduce blanket tariffs on all imports from China, Mexico and Canada as soon as he is sworn in next January.

In a post on his Truth Social network, Mr Trump stated that he will sign an executive order on his first day in office (January 20th) that will implement a flat 25 percent levy on all products entering the country from Mexico and Canada, while Chinese imports will be subject to an extra ten percent duty on top of any existing tariffs.

The three countries are the US' largest trading partners and between them account for 40 percent of the $2.6 trillion worth of goods imported to the US every year.

Tariffs on Canada and Mexico would appear to be a breach of the US-Mexico-Canada (USMCA) trade agreement that was finalized during Mr Trump's first term in office. Last year, 83 percent of Mexican exports went to the US, as did 75 percent of Canadian exports.

Responding to the news, a spokesperson for Mexico's finance ministry said: "Mexico is the United States' top trade partner, and the USMCA provides a framework of certainty for national and international investors."

Meanwhile, the Chinese embassy in Washington told the BBC: "China believes that China-US economic and trade cooperation is mutually beneficial in nature. No one will win a trade war or a tariff war."

Mr Trump said the tariffs would be designed to put pressure on the countries to stop migrants and illegal drugs - particularly fentanyl - entering the US. He alleged that China, Canada and Mexico were not doing enough to crack down on such smuggling, adding that the US' neighbors can "easily solve this long simmering problem".

He also stated that the tariffs would remain in effect until the flow of fentanyl and illegal immigrants to the US stops.