U.S. President Donald Trump will attend a summit of leaders of NATO nations on May 25 in Brussels, the White House said on Tuesday.

Trump's visit will give him an opportunity to press his case for why many NATO allies need to boost defence spending to help spread the cost of the security umbrella.

Trump has made key European allies nervous with his demands that they increase defense spending and his talk of establishing an alliance with Russia to counter Islamic State militants.

"The president looks forward to meeting with his NATO counterparts to reaffirm our strong commitment to NATO, and to discuss issues critical to the alliance, especially allied responsibility-sharing and NATO's role in the fight against terrorism," a White House statement said.

Trump will welcome NATO Secretary General Jens Stoltenberg to the White House on April 12 to discuss "how to strengthen the alliance to cope with challenges to national and international security," the statement said.

Some Democrats had been critical when learning earlier this week that secretary of state Rex Tillerson would not be attending a NATO meeting in early April.