BRUSSELS — The outgoing Dutch prime minister, Mark Rutte, has been formally selected as the next NATO secretary-general, the military alliance announced Wednesday, coming at a pivotal time as it grapples with boosting its own security while also supporting Ukraine in its grinding war against Russia.

His appointment comes after Romanian President Klaus Iohannis – his only rival for the position – announced last week that he had withdrawn from the running.

“It is a tremendous honor to be appointed Secretary-General of NATO. The Alliance is and will remain the cornerstone of our collective security,” Rutte said in a post on X Wednesday.

The Dutch leader, 57, said he was grateful to the NATO allies for placing their trust in him. “Leading this organization is a responsibility I do not take lightly,” he said.

Rutte is set to start his new position on October 1 when incumbent NATO chief Jens Stoltenberg’s 10-year tenure comes to an end, according to a statement from the alliance.

Stoltenberg said Wednesday that he “warmly welcomes” the appointment of his successor.

“Mark is a true transatlanticist, a strong leader and a consensus-builder. I wish him every success as we continue to strengthen NATO,” he posted on X.

The secretary-general is the alliance’s top international civil servant. The person in that role chairs all of NATO’s major committees, is its principal spokesperson and the head of the organization’s international staff.

Rutte will inherit a NATO that is racing to bolster its own security while also supporting Ukraine’s defense against Russia’s invasion. The alliance is walking a tightrope of rearming and increasing military spending while avoiding provoking Moscow and escalating what is already the deadliest war on European soil in decades. — CNN