The UK Prime Minister's Office has said the country will not hesitate to retaliate if the US does not honour its tariff deal with the UK.

But the office said "nobody wants a trade war".

The UK's move comes after US President Donald Trump imposed a 15 per cent tariff on all imports from the UK from Tuesday.

A spokesman for the Prime Minister's Office said most of the UK-US agreements, such as tariffs on cars, steel and medicines, were not expected to change.

However, the spokesman said the situation was "evolving" and that talks between the UK and the US were continuing.

Meanwhile, the European Union announced on Monday that it had suspended a tariff deal with the United States after Trump threatened to impose higher tariffs on countries that did not comply with the new 15 percent tariff.

The U.S. Supreme Court has ruled that Trump’s global tariffs imposed last year exceeded his authority.

The ruling applies to all tariffs imposed by Trump under the Emergency Economic Powers Act.