BRUSSELS - Former Norwegian premier Jens Stoltenberg was named the next Nato chief, stepping in to take over from current secretary general Anders Fogh Rasmussen at a key moment in Europe.

An economist by training and a radical opponent of the defence alliance in his youth, Stoltenberg takes the helm of the 28-nation transatlantic alliance as Europe worries over a Russian build-up on its eastern fringe after Moscow’s takeover of Crimea. The appointment came quicker than anticipated, with the decision made “without opposition” and after a comfortable consensus grew around Stoltenberg, a diplomatic source said. “I’ve known Jens Stoltenberg for many years and I know he’s the right man to build on NATO’s record of strength and success,” Rasmussen, who hails from nearby Denmark, said on Twitter. Stoltenberg, who is 55, was the only candidate for the job and leaders of NATO’s main powers, including US President Barack Obama and German Chancellor Angela Merkel, had all rallied around the former prime minister in recent weeks.

In almost a decade leading the Norwegian government, Stoltenberg, who is the country’s Labour Party chief, became known as a consensus maker, giving him some of the right credentials to maintain good relations with Russia. Though he never had any particular fondness for defence or security matters, his experience as premier left him with a strong international network and honed his skills as a cross-border negotiator. “This is a key strength given the Ukrainian crisis,” a diplomat said in Brussels, where the NATO headquarters is located. His arrival to NATO comes at a pivotal moment, with fears growing over Russia’s resurgence as a military power to contend with, more than two decades after the end of the Cold War.

Created in the years following World War II as a western bulwark against the Soviets, NATO is now on the frontlines of the crisis in the Ukraine, though the former Soviet state is not a member of the alliance. “We do not seek confrontation but we will not waiver if challenged,” Rasmussen said after a brief meeting with Obama in Brussels this week. During the visit, the US president said that “NATO nations never stand alone” and underlined that the alliance was now patrolling the skies over the Baltics, and had reinforced its presence in Poland.

Polish foreign minister Radoslaw Sikorski, who was also rumoured for the NATO job, congratulated Stoltenberg on his nomination. Sikorski said he was sure the new NATO head “will strive for equal security for all members,” in an oblique recommendation to the alliance to remember its eastern-most members on the borders with Russia. Stoltenberg is set to take office on October 1, after an alliance summit in Cardiff. At that time, the alliance should be in the final stages of pulling out the last of its combat forces in Afghanistan, where NATO troops have been fighting the Taliban for over a decade.