European Council President Donald Tusk welcomes US President Donald Trump at EU headquarters in Brussels on May 25, 2017

European Union president Donald Tusk said talks with US President Donald Trump on Thursday revealed no "common position" on Russia, a subject on which the US leader faces pressure at home.

Tusk, along with European Commission President Jean-Claude Juncker, also argued for the benefits of open trade and the Paris climate agreement that Trump is opposed to.

Those issues "remained open", Tusk said, though an EU official said the sides agreed to set up an EU-US task force on trade.

"I'm not 100 percent sure that we can say today -- 'we' means Mr President and myself -- that we have a common position, common opinion about Russia," Tusk said after meeting Trump at EU headquarters in Brussels.

"Although, when it comes to the conflict in Ukraine it seems that we were on the same line," he said, in apparent reference to ongoing sanctions against Russia over its annexation of Crimea and over fighting in eastern Ukraine between government forces and pro-Russia rebels.

The unusually pointed remarks by Tusk, a former Polish prime minister, come as Trump is under fire domestically over allegations that Russia intervened to help his election campaign last year.

The US side meanwhile "expressed concern that jobs in the US would be lost because of Brexit", an EU source said.

Trump had previously backed Britain's vote to leave and said it would be good for both Britain and the EU.

Juncker, whose commission handles trade for the EU's 28 member states, "insisted on intensifying trade cooperation which is a win-win situation for both sides," a spokeswoman for the commission said.

The meeting took place at the EU's new "Europa" headquarters in Brussels on the same day Trump attends a NATO summit, also in the Belgian capital.

As they sat for the talks, Juncker and Tusk tried to make light of the EU's complicated institutional structure to a US president that has been highly critical of the bloc.

"You know Mister President we have two presidents in the EU," Tusk told Trump as the men posed for cameras ahead of the talks.

"There's one too much," said Juncker, making a joke of his traditional rivalry with Tusk.

The leaders' meeting quickly expanded to wider talks where Trump also met with European Parliament President Antonio Tajani and EU diplomatic chief Federica Mogherini.

Secretary of State Rex Tillerson, Defense Secretary Jim Mattis and economic advisor Gary Cohn attended on the US side.

The visit with Tusk and Juncker is a victory of sorts for the EU, which had worked behind the scenes to secure a first encounter with Trump.