In a telephone conversation with NATO Secretary-General Jens Stoltenberg on Sunday, President Donald Trump agreed to a meeting in May with leaders of the North Atlantic Treaty Organization. The summit is to be held in Brussels.

The White House said Trump and Stoltenberg talked about “how to encourage all NATO allies to meet their defense spending commitments” during their phone call. Presumably, this will also be a topic at the Brussels meeting, though CNBC notes that, after Trump’s election, “European NATO members have upped spending to the point that the group’s military spending this year is expected to bounce back for the first time since 2010.”

CNBC adds that Trump also discussed “the potential for a peaceful resolution of the conflict” in Ukraine. Russia’s provocations in the Baltics are said to be one of the reasons European defense spending rebounded, along with the menace of the Islamic State.

The Wall Street Journal reports that officials have yet to determine the precise date for the Brussels summit, but it will probably happen either just before, or after, the Group of Seven meeting in Italy in May.

Secretary of Defense James Mattis is scheduled to meet with NATO defense ministers in Brussels next week, to talk about “what the alliance is doing to fight terrorism and how it can expand its efforts to meet the challenge from the Trump administration including stepping up its intelligence sharing, and bolstering its work with special operations forces,” according to the WSJ. Stoltenberg is also due to meet with Vice President Mike Pence in Brussels after the Munich Security Conference begins on February 17.

During a visit to CENTCOM headquarters in Florida on Monday, President Trump said, “We strongly support NATO. We only ask that all of the NATO members make their full and proper financial contributions to the NATO Alliance, which many of them have not been doing. Many of them have not been even close. And they have to do that.”