Analysts have warned tariffs could push up prices for US households and could also have a knock on effect on consumers across the world, including the UK.

Trump threatened to impose the tariffs, which are a tax added to a product when it enters a country – on Canada, Mexico and China in response to what claims is the unacceptable flow of illegal drugs and illegal immigrants into the US.

But Canadian Prime Minister Justin Trudeau said his country was responsible for less than 1% of fentanyl entering the US and would retaliate with 25% tariffs on $150bn worth of US goods.

“There is no justification for [the US’s] actions…Canada will not let this unjustified decision go unanswered,” Trudeau said in a statement on Monday.

He said Canada would first target $30bn worth of products, and target the remaining $125bn over 21 days.

Any fresh duties Canada imposes will be in place “until the US trade action is withdrawn”, he said, adding that his country would pursue “non-tariff measures” should US tariffs not cease – without specifying what those measures were.

China swiftly announced its own counter measures, which include 10-15% tariffs on some US agricultural goods, including wheat, corn, beef and soybeans. China is the US’s biggest buyer of these goods.

“If the United States… persists in waging a tariff war, a trade war, or any other kind of war, the Chinese side will fight them to the bitter end,” foreign ministry spokesman Lin Jian said.

Before the US tariffs on Mexican imports came into force, President Claudia Sheinbaum said her country had contingency plans.

“In this situation, we need composure, serenity, and patience. We have Plan A, Plan B, Plan C, and even Plan D,” she said.

Sheinbaum said she would speak more about Mexico’s response on Tuesday.