WASHINGTON — The NATO alliance has a new top military adviser, with the exit of Czech Gen. Petr Pavel as Chairman of the NATO Military Committee.

Pavel, who has held the spot for the last three years, formally stepped away from the role on Friday, handing over control to Air Chief Marshal Sir Stuart Peach, the former chief of defence staff of the British Armed Forces.

The chairman of the Military Committee is NATO’s senior military officer, although the top uniformed spot in the alliance is the Supreme Allied Commander Europe, held by the top American general in Europe. However, the chairman plays an important role as the military adviser to the secretary general and works to build consensus from the 29 chiefs of defense.

Pavel was the first Czech to hold the role, but Peach becomes the fifth general from the U.K. to fill the spot. Overall, Germany (five times); the United Kingdom (four times); Canada, Italy and Norway (twice); Belgium, the Czech Republic, Denmark and the Netherlands have all held the chairmanship.

Having taken office just a few months after Russia’s invasion of Ukraine, Pavel oversaw a significant evolution at NATO, as the alliance was forced to quickly react to a resurgent threat on the eastern flank while also continuing to handle operations in the Middle East and migrant challenges in the Mediterranean.

He was also one of the first NATO officials to be outspoken on the issue of Turkey purchasing the S-400 air defense system from Russia, and the potential consequences for their role in the alliance — an issue that has since grown, with the U.S. Congress now considering blocking Turkey from getting its F-35 fighter jets as a result of the S-400 decision.

“We have done a good job moving the Alliance forward, but there is more to come. The Military Committee is a great band of brothers who have always held frank and open discussions,” Pavel said in remarks shared by NATO. “If we keep in mind and support the core values of the Alliance, then we can always deal with any differences or disagreements. The role of this body will always be to provide fair military advice.”

Peach takes over at another potential inflection point, with tensions between the United States and its NATO allies remaining an issue. And the British officer, who joined the Royal Air Force in 1977, will also have to deal with potential strains from Brexit causing some European nations to invest in defense internally through the European Union, rather than through NATO.

Said Peach, “I look forward to continuing the process of modernization, increasing readiness and reviewing our Command Structure. Through this work we will ensure that NATO is credible on a global stage and remind those who would do us harm that while we have the most powerful and best equipped alliance in history, our strength is our unity.”