Europe must unite against Trump's America First policy: German FM

"Obviously it irritates us when President Trump describes Europe as an enemy of the USA in the same breath as Russia and China or calls NATO into question almost as a throwaway remark," said Maas in Bucharest on Monday.

"It seems absurd that we in the European Union have to worry about reacting to US tariffs that are justified on national security grounds," he added.

He further noted that such an "absurdity" could be a sign of a changing geo-political climate.

"'America First' was a wake-up call. Our answer to that must be: 'Europe United!," he stressed.

Mass also called on the EU to develop a "common foreign and security policy worthy of the name."

The remarks were made during a global trade war between the EU and Washington.   

 Last week, Maas warned that Europe will not give in to threats by the administration of Trump.

"Europe will not be threatened by President Trump. If we cede once, we will often have to deal with such behavior in the future,” Heiko Maas said in a post on Twitter on Tuesday.

Earlier in the day, French President Emmanuel Macron said he will announce new proposals for the European Union to boost its security, calling on the 28-member bloc to stop relying on the United States to protect its sovereignty.

“Europe can no longer rely on the United States for its security. It’s up to us to meet our responsibilities and guarantee our security, and therefore European sovereignty,” said Macron said during a speech in Paris.