NATO names Stoltenberg as next chief Former Norwegian prime minister will head the Western military alliance.

Anders Fogh Rasmussen has announced that his successor as secretary-general of NATO will be Jens Stoltenberg, the former Norwegian prime minister.

Rasmussen’s announcement, made via Twitter, followed endorsement of Stoltenberg’s appointment today by the ambassadors of the military alliance’s 28 member states.

The 55-year-old Stoltenberg has twice been his country’s leader, in 2000-01 and from October 2005 to October 2013.

He will take up the post on 1 October, shortly after a NATO summit in Cardiff.

The mandate of Rasmussen, a former Danish prime minister, had been extended to include the summit.

Stoltenberg will take up office just as most, possibly all, NATO troops are preparing to leave Afghanistan and at a point when Russia’s annexation of Ukraine’s Crimean peninsula is forcing a re-think of NATO policy.

One early change may be a redeployment of military assets from western to central and eastern Europe, including US troops. Almost all US forces in Europe are stationed in the continent’s western half.

Sweden’s foreign minister, Carl Bildt, tweeted that he had “no doubt” that Stoltenberg was a “good choice”, adding: “Intimate knowledge also of northern European security issues a plus.”

Neither Sweden nor Finland is a member of NATO.

Bildt may also have been referring to concerns that the Arctic may become increasingly militarised as its ice cover thins and retreats because of climate change.

Arctic issues are governed by eight countries, including Russia. Of the other seven countries, all are members either of NATO or of the European Union or both: Canada, Denmark, Finland, Iceland, Norway, Sweden and the United States.