Former Norwegian premier Stoltenberg -- at the helm of the Western military alliance since 2014 -- already had his tenure prolonged a year, to October, in the wake of Russia's invasion of Ukraine in February 2022.

Multiple diplomats at NATO confirmed that its 31 member states had reached consensus to prolong the tenure of Stoltenberg, 64, for another year after struggling to find a suitable replacement by a summit in Lithuania in two weeks.

Others seen as potential candidates, including Danish Prime Minister Mette Frederiksen and British Defence Minister Ben Wallace, have recently dropped out of contention.

US ambassador to NATO Julianne Smith did not confirm any agreement.

But she told journalists an announcement on the secretary general's position would likely be made "in the days ahead".

"A possible extension of Jens Stoltenberg is an option that allies are looking at," Smith said.