https://www.bbc.co.uk/newsCanada, Mexico and China have vowed to respond to sweeping new tariffs to their exports to the US announced by President Donald Trump.
Trump said a levy of 25% on Canadian and Mexican imports as well as an additional 10% tax on Chinese goods would come into force on Tuesday. Canadian energy faces a lower 10% tariff.
The US president said the move was in response to his concerns about illegal immigration and drug trafficking - two of the main promises on which he was elected.
In response, both Canada and Mexico said they were preparing similar tariffs on US goods, while China added it would take "necessary countermeasures to defend its legitimate rights and interests".
The implementation of tariffs and the subsequent retaliation could mark the start of a new era of global trade wars.
Economists have warned the introduction of the import taxes by the US, and the responses from other countries could lead to prices rising on a wide range of products, from cars, lumber, and steel to food and alcohol.
But Trump has indicated he is ready to escalate the duties further if the countries retaliate.