Stoltenberg tweeted Thursday that he is "honored'' by the decision of NATO leaders to extend his term until 30 September 2023.

"As we face the biggest security crisis in a generation, we stand united to keep our Alliance strong and our people safe,'' he said.

The former Norwegian prime minister was named to NATO's top civilian post in October 2014. It's the second time that his term of office has been extended. His mandate was due to expire in September.

In February, Norway's government appointed Stoltenberg as head of the Scandinavian country's central bank and said it hoped he could start in his new role around Dec. 1. It later said that deputy governor Ida Wolden Bache would be in charge until Stoltenberg can take over.