European Union officials have drawn up plans to impose levies on American imports, but questions abound about whether they would go through with them.

The US is imposing a 17% tariff on most tomatoes imported from Mexico with immediate effect, the government said. The duty came into force after the US withdrew from a long-standing agreement with its southern neighbour, arguing that the deal "had failed to protect US tomato growers from unfairly priced Mexican imports".

President Donald Trump expanded his tariff threats over the weekend, calling for 30% levies on two of America’s largest trading partners: the European Union and Mexico.