WATFORD, England (AP) — NATO leaders sought Wednesday to paper over differences like the military alliance’s future priorities but insisted they would respond as one in the event of an attack on any of the 29 member countries.

Ending a summit just north of London to mark NATO’s 70th anniversary, the leaders announced that they would set up a commission of experts to study political decision-making. That appears to be a direct response to French President Emmanuel Macron’s recent lament about the “brain death” of the trans-Atlantic alliance.

“We stand together, all for one and one for all,” NATO Secretary-General Jens Stoltenberg told reporters after chairing the meeting at a luxury hotel and golf resort. “Our commitment to Article 5, the collective defense clause of our alliance, is iron-clad.”

Ahead of the summit, Macron had complained about a lack of U.S. leadership. President Donald Trump branded his remarks as “very disrespectful,” while Turkish President Recep Tayyip Erdogan suggested that Macron himself was “brain dead.”

The infighting is mostly due to Turkey’s offensive in northern Syria, which began in October. Macron has complained that Trump pulled U.S. troops out of the region without warning his NATO allies; a move that Turkey saw as a greenlight to send its troops in.

Countries across the European Union are particularly concerned as to what may transpire. The worry in many EU capitals is that some extremist fighters escaped during Turkey’s offensive, and that the fighting could spark a new wave of refugees.

To help ease tensions, leaders agreed to “a forwarding-looking reflection process” to be led by Stoltenberg. Details were sketchy, but the commission, “drawing on relevant expertise,” would study ways “to further strengthen NATO’s political dimension including consultation.”

Germany and France had both put forward similar schemes, although Macron riled many allies with his pre-summit remarks and NATO officials have pointedly suggested that they were more impressed by Berlin’s proposal.

After three summits in consecutive years, the leaders decided that they would take a year off and meet again in 2021. That means there won’t be another one until after the next presidential election in the United States, which is by far NATO’s most powerful and influential member country.

Summit host Prime Minister Boris Johnson — also busy with a divisive British election campaign — was upbeat, saying “there was a mood of very great solidarity and determination and a willingness to push NATO forward, not just for the next few years but for the next 70 years.”

There were a few sour notes though. Erdogan didn’t speak to waiting media. Trump arrived via a different entrance, away from media, and said he would leave without holding a news conference.