BRUSSELS • EU chief Donald Tusk warned yesterday that US President Donald Trump's administration was a "threat" facing the 28- nation bloc, along with China, Russia and radical Islam.

In a strongly worded letter to EU leaders ahead of a summit in Malta, Mr Tusk said the bloc must take "spectacular steps" to stay together, and should take advantage of Mr Trump's isolationism to boost trade with other countries.

"Particularly, the change in Washington puts the European Union in a difficult situation, with the new administration seeming to put into question the last 70 years of American foreign policy," he said.

EU leaders have become increasingly concerned by Mr Trump's recent ban on migration from seven Muslim countries, plus comments in which he appeared to back Britain's exit from the EU and the eventual break-up of the union.

On Monday, tens of thousands of people protested in London and other British cities against Mr Trump's travel ban.

Some chanted "Shame on May" over British Prime Minister Theresa May's offer to Mr Trump of a visit to Britain, while 1.6 million people signed a petition calling for Mr Trump's planned trip - which will involve lavish displays of royal pageantry and a banquet hosted by Queen Elizabeth - to be cancelled.

French Foreign Minister Jean-Marc Ayrault said on Monday that the US should revoke these "dangerous" new immigration measures, and demanded "an urgent clarification as soon as possible from the Americans".

He said France would double the number of visas available for Iranians this year, partly in response to the ban.

"The welcoming of refugees is a duty and question of solidarity," he said. "Terrorism doesn't have a nationality, and discrimination is not a response."

German Chancellor Angela Merkel also stepped up her criticism of the ban, saying it smacked of an anti-Muslim bias.

REUTERS, AGENCE FRANCE-PRESSE