North Korea worked through 2016 on developing components for an intercontinental ballistic missile, making the isolated nation's claim that it was close to a test-launch plausible, international weapons experts say. (Reuters)

President-elect Donald Trump contended Monday night that North Korea would not be able to develop a nuclear weapon capable of reaching the United States, despite its claims to the contrary, and berated China for not doing enough to help stop the rogue state's weapons program.

Trump's declarations on Twitter came after North Korean leader Kim Jong Un said in a New Year's address that the country had reached the “final stages” of testing its first intercontinental ballistic missile that could reach the United States.

“It won't happen!” Trump tweeted.

The president-elect — who spent Monday with advisers at Trump Tower in New York following his holiday respite in Florida — did not specify what, if anything, the United States might do under his command to stop North Korea from developing the missile.

In a second tweet, Trump sought to shame Chinese leaders for trading with the United States but doing little to help stop North Korea's development of nuclear weapons.

He tweeted: “China has been taking out massive amounts of money & wealth from the U.S. in totally one-sided trade, but won't help with North Korea. Nice!”