Secretary of State Marco Rubio is visiting NATO’s headquarters in Brussels for a meeting of the alliance’s foreign ministers, putting him on the front lines of the Trump administration’s push against traditional American allies in Europe.

European leaders were already bracing for a contentious gathering. President Donald Trump’s decision to pull back aid from Ukraine amid its efforts to fight off Russia’s invasion marked a dramatic break with other allies, while his decision to engage Moscow in direct, one-on-one negotiations has left the continent’s diplomats back on their heels.

But on Wednesday, shortly before Rubio was set to depart for Belgium, Trump unveiled sweeping new “reciprocal” tariffs — including a 20% tax on imports from the European Union.

So far, Rubio has declined to address the tariff issue head on, but his Canadian counterpart said the global economic shock made it difficult to focus on the meeting’s pressing agenda.

“Clearly we’re passing that message to our American counterparts that it’s difficult to have these [NATO] conversations in the context of a trade war,” Foreign Minister Mélanie Joly said in an interview with CNN.

Rubio has also tried to skirt another topic of contention: Trump’s stated desire to “get” Greenland for the United States by any means necessary.

Rubio met with Danish Foreign Minister Lars Lokke Rasmussen on the sidelines of the NATO ministerial but didn’t respond to reporters’ questions asking what he would say about Greenland during the session. The State Department also made no mention of the Danish autonomous territory in its readout of the engagement.

“Secretary Rubio reaffirmed the strong relationship between the United States and the Kingdom of Denmark,” State Department spokeswoman Tammy Bruce said. “They discussed shared priorities including increasing NATO defense spending and burden sharing and addressing the threats to the alliance, including those posed by Russia and China.”

Rasmussen later said his meeting with Rubio was “good” but that while Greenland was not on the agenda “for many reasons,” he had still taken the opportunity “to very strongly object to claims and presidential statements of a vision of acquiring Greenland.”

It has amounted to a situation in which it’s not within the limits of international law,” he said, calling it “an attack on Danish sovereignty.”

“We have seen these statements from the president, and we can’t accept that,” Rasmussen added. “And I made it very, very clear.”

Rubio and Rasmussen’s meeting comes just days after Vice President J.D. Vance visited Greenland alongside his wife, Usha Vance, and national security adviser Mike Waltz.

The second lady was originally scheduled to headline the trip and spend several days on the world’s largest island, taking in Greenlandic cultural sites, but the visit sparked backlash from Greenland’s interim government and Danish leaders who noted an invitation was never extended.

In the aftermath, the White House added the vice president to the traveling delegation and whittled down the itinerary, shortening the trip to a one-day stop at a remote American military base in northwestern Greenland.

Rubio has taken a more measured approach in his comments about Greenland than the president, but he still emphasized what he said are the pressing U.S. national security concerns surrounding control of the island.

“This is not a joke,” Rubio said in January. “This is not about acquiring land for the purpose of acquiring land. This is in our national interest, and it needs to be solved.”

At NATO Headquarters on Thursday, Rubio tried to reassure allies that despite the president’s mixed signals, the Trump administration still views the alliance as central to U.S. security.

“President Trump’s made clear he supports NATO. We’re going to remain in NATO,” he said.

Still, Rubio pushed the administration’s message that allies need to increase their defense spending — calling on all of the alliance’s members to commit to putting up to 5% of their annual GDP toward it, a sharp uptick from the previous 2% benchmark.

“We do want to leave here with an understanding that we are on a pathway, a realistic pathway,” he said. “That includes the United States that will have to increase its percentage.”