EFEWashington DC

The United States president on Saturday attacked the European Union over what he perceives as an unfair trade relationship, saying the block was established to take advantage of the US.

Donald Trump was speaking to supporters at an election campaign-style rally near Detroit, Michigan.

"When we take on the European Union, which has tremendous blocks, it's very hard for us to sell stuff into the European Union. It was put there to take advantage of the US", Trump said.

"Not anymore. Those days are over. But we've got to open up these markets, it's not fair", the president added.

During his rambling speech, which lasted well over an hour and touched on a wide range of topics, Trump repeated his campaign promises to "straighten out" "disastrous" deals such as the North American Free Trade Agreement, which he said had led to farmers "doing lousy for 15 years", or the Iran nuclear deal.

This week, the president hosted both French president Emmanuel Macron and German chancellor Angela Merkel, who traveled to Washington in an effort to convince Trump not to back out of the Iran deal, signed in 2015 by his predecessor Barack Obama.

Trump is expected to announce whether he will withdraw from the agreement by May 12.

Macron and Merkel were also in Washington to pressure the US president into not applying a 25 percent tariff on steel imports and 10 percent for aluminium, from which the EU has so far been exempt.

Trump has until Tuesday to decide whether to extend that exemption.