Trump, who will stay in his Manhattan penthouse at Trump Tower, will conclude his stay on Thursday with meetings with leaders from Turkey, Afghanistan and Ukraine before holding a lunch with the leaders of South Korea and Japan, largely to discuss the threats emanating from North Korea.
"What we have to do, is call on all nations, call on everyone to do everything they can", said McMaster.
Since President Trump threatened North Korea with "fire and fury" in August, the North has conducted its most powerful nuclear test, threatened to send missiles into the waters around the U.S. Pacific island territory of Guam and launched two missiles of increasing range over Japan.
North Korea has launched dozens of missiles under Kim Jong Un's leadership to accelerate a weapons programme created to give it the ability to target the United States with a powerful, nuclear-tipped missile. "This includes the regime of North Korea, which has one again shown its utter contempt for its neighbors, and the entire world community".
Trump's Tuesday morning speech will promote peace and prosperity while upholding sovereignty and accountability, said McMaster.
With San Francisco or NY in Kim's cross-hairs, would President Trump risk war with the North to defend Seoul or Tokyo in a future crisis? When the UN Security Council refuses to act in Syria, or when UN peacekeepers abuse those they are supposed to protect, or when scandals like Oil-for-Food expose corruption and cronyism, or when bodies like the UN Human Rights Council go off the rails, the understandable response is outrage. While Washington warns of military options, it says it still wants a peaceful solution.
With Haley leading the way, the United Nations has placed increased sanctions on North Korea due to its belligerent behavior regarding its nuclear program.
"The members are starting to get us to act, whether it is with United Nations reform, whether it's with peacekeeping, we are starting to see a lot of changes".
McMaster said that reform of the U.N.is very much on the table at the meeting in general, with focus on ideas for making the notoriously inefficient organization, whose biennial core budget is $5.4 billion, more streamlined.
"What we are seeing is they continue to be provocative, they continue to be reckless".
"For those who have been commenting about the lack of a military option, there is a military option", he said. That, she added, "is just the beginning of what we can do". "I don't think he meant anything beyond that".
North Korea fired the intermediate-range ballistic missile over Japan that landed in the Pacific, responding to new United Nations sanctions with its furthest-ever missile flight.
The ambassador said she has "no problem kicking it to Gen. Mattis", the U.S. Defense Secretary, because "I think he has plenty of options".