WASHINGTON -- US National Security Adviser Robert O'Brien warned North Korea Sunday that the United States has many "tools in its toolkit" to respond to any major provocation and will use them to demonstrate its disappointment.

Brien made the comments in an interview with ABC amid concerns North Korea could be preparing to launch an intercontinental ballistic missile to express its frustration over stalled denuclearization talks with the US.

North Korea's regime has set the end of the year as the deadline by which Washington must offer concessions in their talks and threatened to take a "new way" unless its demands for sanctions relief and security guarantees are met.

"We'll reserve judgment, but the United States will take action as we do in these situations," O'Brien said. "If (North Korean leader) Kim Jong-un takes that approach, we'll be extraordinarily disappointed and we'll demonstrate that disappointment."

Asked about the possible consequences of a long-range missile or nuclear test, O'Brien declined to speculate.

"But we have a lot of tools in our toolkit," he said, "and additional pressure can be brought to bear on the North Koreans."

O'Brien noted that the US remains the leading military and economic power in the world.

Recent days have seen heightened tensions over North Korea's threat to send an unwelcome "Christmas gift" to the US unless Washington takes steps to salvage the negotiations.

Christmas passed without a "gift," but South Korean and US officials have remained on high alert amid assessments the window for a provocation has not yet closed.

O'Brien suggested that Kim may have changed his mind on the basis of his good personal relationship with US President Donald Trump.

"So perhaps he's reconsidered that," he said. "But we'll have to wait and see."

On Christmas Eve, Trump brushed off the North's warning, saying the US will find out what the surprise is and "deal with it very successfully."

"Maybe it's a nice present. Maybe it's a present where he sends me a beautiful vase as opposed to a missile test," he quipped.

Trump and Kim have met three times starting in June 2018 to try to reach a deal on denuclearizing North Korea in exchange for US concessions, but negotiations have been deadlocked since their second summit in February due to wide gaps over how to match their steps. (Yonhap)