According to the official, Freeland is the prime candidate that has surfaced in Washington.
The United States is unlikely to put forward an American candidate since a US general is traditionally appointed as the Supreme Allied Commander Europe, the report said.
Estonian Prime Minister Kaja Kallas, Slovak President Zuzana Caputova, and ex-Croatian President Kolinda Grabar-Kitarovic, who also was Croatia's ambassador to the US and an assistant secretary general for public diplomacy at NATO, are named as strong contenders from the European Union, according to the report. UK Defense Secretary Ben Wallace is another contender for the post, the newspaper cited UK officials as saying.
The newspaper also cited a NATO official as saying that NATO member states could agree to extend Stoltenberg's term in office by another year in September.
A NATO source told Sputnik in mid-October that ex-Italian Prime Minister Mario Draghi is most likely to become the next NATO chief since the alliance is looking for a former high-ranking official with a deep understanding of the European security architecture amid the Ukraine crisis.
Stoltenberg's term as secretary general was due to expire this fall, but his term was extended for another year, until September 30, 2023, against the backdrop of the Ukraine crisis.