NATO members are expected to agree on Tuesday to extend the term of Secretary General Jens Stoltenberg for a further year, according to four diplomats.

The decision has been widely signaled in recent weeks, but ambassadors to NATO are expected to formally approve the extension during a meeting on Tuesday, said the diplomats, who spoke on Monday on condition of anonymity.

Stoltenberg has guided NATO through a series of crises since taking charge in 2014, most recently rallying NATO members in support of Ukraine while seeking to prevent the war there from escalating into a direct conflict between NATO and Russia.

Stoltenberg, 64, is a former prime minister of Norway. He was due to complete his term as the top civilian at the transatlantic security alliance at the end of September but is now likely to stay on for a further 12 months.

Stoltenberg said in February that he was not seeking an extension to his contract. But NATO members asked him to accept one after failing to reach consensus on a successor.

Among those discussed as contenders were British Defence Secretary Ben Wallace — who openly said he would like the job — and Danish Prime Minister Mette Frederiksen, who insisted publicly that she was not a candidate for the post.