US National Security Advisor Robert O’Brien with Donald Trump, September 8, 2019 (AP)

Donald Trump’s National Security Advisor Robert O’Brien says the US is ready to act if North Korea delivers its “Christmas gift” of a long-range missile test.

O’Brien said in a TV interview on Sunday, “If [North Korean leader] Kim Jong Un takes that approach, we’ll be extraordinarily disappointed and we’ll express that disappointment.”

Last week Pyongyang further buried Trump’s photo-opportunity summits with Kim, saying its gift would arrive if the US did not ease sanctions by the end of the year. US officials are preparing for a missile test into the Pacific.

North Korean State media said high-level officials convened on Saturday to address the “manifold and harsh trials and difficulties” facing the country, with discussions continuing on Sunday.

Kim is due to deliver a speech on New Year’s Day.

O’Brien said the White House is monitoring the situation, but would not comment on a specific response if North Korea carried out a missile test.

“[We have] a lot of tools in our toolkit,” he said. “Additional pressure can be brought to bear….We’ll reserve judgement but the US will take action.”

The Administration has pre-approved options such as flights of bombers over the Korean Peninsula to military drills of ground weapons.

After threatening war with North Korea throughout 2017, Trump switched to the pursuit of summits, eventually meeting Kim three times and becoming the first US President to step foot inside North Korea.

However, North Korea used the meetings to sustain its position on nuclear weapons and missiles, doing no more than signing a general, two-page document about “denuclearization” of the Korean Peninsula.

See also He Came to North Korea. He Shook Hands. Then Trump Retreated.

Kim walked out of the February 2019 in Hanoi, Vietnam. After Trump’s step into the Korean Demilitarized Zone on June 30, the two sides announced the resumption of “working-level” nuclear talks, but discussions broke down in October.

Asked if there has been any resumption of contact, O’Brien said only, “There are channels of communication.”

When the interviewer cited North Korea’s renewed insult of Trump as a “dotard” — issued by Kim Yong-Chol, the senior advisor of Kim Jong Un — O’Brien responded: “It’s their way of trying to negotiate.”