Brussels and Washington's attitudes "remain open" on issues like trade and climate change though they agree on collective action against terrorism, European Council President Donald Tusk said after his meeting with US President Donald Trump on Thursday morning.

US President Donald Trump (R) walks with the President of the European Council Donald Tusk in Brussels, Belgium, May 25, 2017.  [Photo/Agencies]

"My feeling is that we agreed on many areas. First and foremost, on counter-terrorism, and I am sure that I do not have to explain why. But some issues remain open, like climate and trade," Tusk said.

The meeting was held amid tight security in European headquarters zone, with public access to the area being cut off and a heavy security and police force presence.

Tusk said both sides covered foreign policy, security, climate and trade relations though the White House has not released any information so far.

But Trump has warned he would backtrack on the Paris Climate Change Agreement, and he killed the Trans-Pacific Partnership, although his final position on the Trans-Atlantic Trade and Investment Partnership is still to be announced.

Tusk said: "I am not 100 per cent sure that we can say today - we meaning President Trump and myself - that we have a common opinion about Russia, although when it comes to the conflict in Ukraine, it seems that we were on the same line."

He offered no further explanation.

The relationship between EU and Russia is still not back on track, with EU sanctions remaining in place.

Trump is expected to urge the EU to share more of the budget burden of the NATO military alliance as he attends a summit of NATO leaders in Brussels on Thursday afternoon.

European Commission President Jean-Claude Juncker, European Parliament President Antonio Tajani and High Representative Federica Mogherini also joined Tusk in meeting with Trump in the Europa building in Brussels.

The European Union labelled the meeting with Trump as a leaders meeting, instead of summit. Trump has shared various views with his European counterparts on globalization, migrants, trade and climate during his election campaign last year.

The analysts said Trump should take the chance to enhance trust and ease off criticizing European.

Tusk said his main message to Trump was that what gives cooperation and friendship its deepest meaning are fundamental Western values, like freedom, human rights and respect for human dignity.

"The greatest task today is the consolidation of the whole free world around those values, and not just interests," said Tusk.

"Values and principles first - this is what we, Europe and America, should be saying."

After the NATO summit, Trump will heads to Italy to participate in G7 summit, which will be held on Friday and Saturday.

But Elke Fimmen, senior researcher of Schiller Institute in Germany urged the leaders from the West to change their old paradigm of dialogues during the summit to fit into the changed global situation to achieve common peace and prosperity.

"One dominating dynamic worldwide is wide acceptance of Beijing's Belt and Road Initiative and when leaders meet, they must know that the win-win cooperation for joining global economic development is essential," said Fimmen.

Fimmen said now the Europe is crises while the Belt and Road Initiative has served as the new paradigm for the future development, aimed at being helpful for European development.

"We should adjust our policies into this new paradigm and I think the present EU policies are not adequate to change the problems," said Fimmen.