The United States stopped operating a surveillance flight around the Korean Peninsula, an aviation tracker said Sunday, as North Korea did not follow through on its threat to deliver a "Christmas gift."

Aircraft Spots tweeted earlier Sunday that "there is no RC-135S Cobra Ball operating" over the waters off South Korea for the first time in nearly five days.

The US had carried out a surveillance mission over the East Sea from Tuesday through Saturday in an apparent move to monitor North Korea's possible provocations around the Christmas holiday.

North Korea has threatened to take a "new way" if Washington fails to come up with a new proposal in their stalled nuclear talks before Pyongyang's self-imposed year-end deadline.

North Korea has said that it is entirely up to Washington what "Christmas gift" it wants to get, sparking speculation that Pyongyang could resume provocative acts such as a launch of an intercontinental ballistic missile.

On Saturday, North Korean leader Kim Jong-un presided over a crucial ruling Workers' Party meeting meant to discuss important matters in the building national defense and to overcome harsh trials and difficulties in apparent reference to the UN sanctions.

North Korea has been under tightened UN sanctions, as well as separate US sanctions, over its nuclear tests and its long-range rocket launches.

North Korea has repeatedly sought the lifting of sanctions, but the US has demanded that Pyongyang take sweeping denuclearization steps, insisting that sanctions relief will follow substantive progress in its denuclearization.

The plenary meeting of the party's Central Committee "goes on," the North's official Korean Central News Agency reported earlier Sunday, without providing any key details.

The meeting comes just ahead of Kim's New Year's speech that will be closely scrutinized by officials and experts in South Korea, the US and other regional powers as it offers clues on the North's policy goals in the New Year.

(Yonhap)