NATO has suffered “brain death,” French President Emmanuel Macron said in an interview published Thursday, warning that the 29-member alliance can no longer coordinate strategically and that its promise of collective defense is now uncertain.

“What will Article 5 mean tomorrow?” the French leader said in an interview with the Economist, referring to the article of the North Atlantic Treaty on collective defense. “If the Bashar al-Assad regime [in Syria] decides to retaliate against Turkey, will we commit ourselves under it? It’s a crucial question.”

Macron’s comments are among the most pessimistic made by a leader of a European NATO power in recent years. They follow years of criticism of NATO by President Trump, who has pursued an “America First” policy and publicly condemned the organization as outdated.

The remarks drew a rebuke Thursday afternoon in Berlin, where German Chancellor Angela Merkel said the French president had used “drastic words” that did not reflect her view. “NATO remains a cornerstone of our security,” Merkel said at a news conference with NATO Secretary General Jens Stoltenberg, who emphasized the need for unity in the alliance.

Some analysts warned that although Macron may be trying to rally European allies with his remarks, his comments could backfire. “This will really damage NATO and could be seized on by its opponents including Trump,” Tom Wright, a senior fellow at the Brookings Institution, wrote on Twitter.

François Heisbourg, a senior adviser at the International Institute for Strategic Studies, wrote on Twitter that “Macron is speaking like a policy-detached think-tanker.” Heisbourg, who advised Macron’s presidential campaign on defense policy issues, warned that such a stance was “bizarre” and “dangerous” for a head of state.

NATO leaders including Macron and Trump are scheduled to meet in London early next month for a summit that will also mark the 70th anniversary of the alliance’s founding. The summit will be held in the wake of tension between Turkey, a NATO member, and others in the alliance over Ankara’s intervention in northeastern Syria in October.

The French leader cited Trump’s negative view of NATO, as well as his belief that it was a “commercial project,” as a particular challenge for European leaders.

“The NATO we’ve known since the beginning is changing its underlying philosophy,” Macron said. “When you have a United States president who says that, we cannot, even if we don’t want to hear it, we cannot in all responsibility fail to draw the conclusions, or at least begin to think about them.”

Macron also said that Trump’s unilateral diplomacy with Turkish President Recep Tayyip Erdogan has undermined the NATO alliance. The Turkish intervention in northeastern Syria began in October after Trump pledged to remove U.S. troops from the area.

A lack of central regulation in NATO allowed these sorts of unilateral moves that run contrary to the interests of other members, the French president said. “So as soon as you have a member who feels they have a right to head off on their own, granted by the United States of America, they do it,” Macron said. “And that’s what happened.”

NATO was founded in 1949 at the start of the Cold War, and for much of its history it was primarily a counterbalance to the Warsaw Pact, a collective defense treaty between the Soviet Union and Eastern Bloc countries.

However, the alliance outlasted the Cold War and found new reasons to exist: On Sept. 12, 2001, NATO invoked Article 5 for the first and so far only time in its history after the United States came under attack from al-Qaeda terrorists.

But Macron said the organization’s future is no longer clear. “The instability of our American partner and rising tensions have meant that the idea of European defense is gradually taking hold,” he told the Economist.

The French president has previously suggested greater military coordination on a European level — a proposal that Trump has criticized. This week, German Defense Minister Annegret Kramp-Karrenbauer announced that Germany would reach a NATO spending goal of 2 percent of economic output by 2031, possibly blunting long-standing U.S. criticisms that it does not contribute enough to the alliance.

NATO is and will remain the anchor of European security. But it is also clear that Europe must increase its own complementary ability to act,” Kramp-Karrenbauer said Wednesday night at a private event to honor Stoltenberg, according to Reuters.

Kramp-Karrenbauer is considered a potential successor to Merkel, who is expected to step down as chancellor in 2021.