European Council President Antonio Costa (left) welcomes France's President Emmanuel Macron as he arrives for an informal EU leaders' retreat at the Palais d'Egmont in Brussels on Monday. (AFP-Yonhap)
European Council President Antonio Costa (left) welcomes France's President Emmanuel Macron as he arrives for an informal EU leaders' retreat at the Palais d'Egmont in Brussels on Monday. (AFP-Yonhap)

The European Union must show its muscle if US President Donald Trump makes good on his threat to target the bloc with tariffs, French President Emmanuel Macron warned on Monday.

"If we are attacked in terms of trade, Europe -- as a true power -- will have to stand up for itself and therefore react," Macron said as he arrived for leaders' talks in Brussels.