President Donald Trump is currently on his way to meet with NATO in Brussels, and he took to Twitter to express his feelings and mindset coming into the meeting. He stated that he is much more optimistic about his meeting with Russian President Vladimir V. Putin, and that he will address the U.S. funding to NATO on his meeting with them.

His tweet, reportedly written before he entered Air Force One, read:

Getting ready to leave for Europe. First meeting – NATO. The U.S. is spending many times more than any other country in order to protect them. Not fair to the U.S. taxpayer. On top of that we lose $151 Billion on Trade with the European Union. Charge us big Tariffs (& Barriers)! … NATO countries must pay MORE, the United States must pay LESS. Very Unfair!”

Even though this may seem like regular behavior for Trump, it is actually very unusual for a president to dismiss the value of NATO and focus on the cost it represents for national spending. The fact that he is going into the meeting with this mentality has worried specialists since his actions could have immense repercussions in the country’s relation with NATO allies. This is especially concerning given the current state of the U.S. government, and it would be a great opportunity for the president to work in favor of relations with other countries.

However, his tweet and statements did not go without response. Surprisingly, E.U. leader Donald Tusk stated on twitter:

Dear . US doesn’t have and won’t have a better ally than EU. We spend on defense much more than Russia and as much as China. I hope you have no doubt this is an investment in our security, which cannot be said with confidence about Russian & Chinese spending :-)”

He also commented on Trump’s constant criticism of Europe after signing a E.U.-NATO agreement. He stated: “Appreciate your allies. After all, you don’t have that many.” The president didn’t seem to be moved by Tusk’s comment, yet also failed to provide a fulfilling answer or prove that the U.S. still has allies that it can rely on.  He responded:

Well, we do have a lot of allies, but we cannot be taken advantage of. We’re being taken advantage of by the European Union.We lost $151 billion last year on trade, and on top of that we spend at least 70 percent for NATO, and frankly it helps them a lot more than it helps us. So we’ll see what happens.”

He has constantly spoken against Trump and his policies, often balancing irony with seriousness over the president’s actions. He has even warned people to always be ready for the worst-case scenario when negotiating with the president. One of his most notable responses was one that followed Trump’s departure from the Iran nuclear deal. He stated on Twitter:

Looking at latest decisions of @realDonaldTrump someone could even think: with friends like that who needs enemies. But frankly, EU should be grateful. Thanks to him we got rid of all illusions. We realise that if you need a helping hand, you will find one at the end of your arm.”