The finance ministers from Europe’s five largest economies have warned the Trump administration that Republican tax cut plans would flout international agreements and undermine trade, threatening to turn a Washington policy battle into a transatlantic row.

In a letter to the White House and US Treasury department, the ministers — including Philip Hammond of the UK, Peter Altmaier of Germany and Bruno Le Maire of France — raised the possibility of retaliating if the legislation becomes law.

The letter highlights concerns in Europe that the Trump administration will use tax reform as a route to promote “America first” trade discrimination, escalating tensions that have already risen in other policy areas like the environment and Middle East peace.