Brussels, 12 February 2023 (dpa/MIA) - NATO Secretary General Jens Stoltenberg is not seeking a further mandate extension and is set to leave his post as planned later this year, the defence alliance has said.

"The mandate of Secretary General Jens Stoltenberg has been extended three times and he has served for a total of almost nine years," NATO Spokesperson Oana Lungescu said on Saturday night at dpa's request.

"The Secretary General's term comes to an end in October of this year and he has no intention to seek another extension of his mandate."

Stoltenberg's mandate was extended until 30 September 2023 in March last year, shortly after the beginning of Russia's invasion of Ukraine.

Recently, there has been speculation that the 63-year-old's term in office could be extended again amid the conflict in Ukraine. At the same time, diplomats have pointed out that this could give the impression that NATO was unable to agree on a new head.

Stoltenberg, a former Norwegian prime minister, has earned recognition as a skilful mediator between NATO's 30 allies, whose interests diverge significantly on some issues.

He is particularly credited with moderating in a dispute on the defence spending of European allies, which escalated during the term of former US president Donald Trump. Trump even threatened at times to withdraw the US from the alliance.

Most recently, Stoltenberg has primarily coordinated NATO's response to the Russian war against Ukraine and promoted extensive arms deliveries to Ukraine.

Stoltenberg is currently NATO's second-longest serving secretary general, eclipsed only by Joseph Luns of the Netherlands who held the post from 1971 to 1984.

It is not yet clear who could take over from Stoltenberg. Former Italian prime minister Mario Draghi and Romanian President Klaus Iohannis have been touted as possible candidates, although the choice often falls on someone other than those previously named.

The 30 alliance members are expected to decide at their July summit in Vilnius at the latest. The decision is unanimous.