Ahead of meetings in New York later this week, Nikki Haley kept up the Trump administration’s hardline rhetoric when she told reporters that if North Korea poses a serious threat to the US or its allies then it “will be destroyed”.
She added that Trump’s earlier statement, when he declared Pyongyang would be met with “fire and fury like the world has never seen” if missile tests continued, was “not an empty threat”.
Speaking to CNN, Ms Haley said: “None of us want war… We wanted to be responsible and go to all diplomatic means to get their attention first.
“If that doesn’t work, General Mattis will take care of it.”
President Trump is set to address the UN General Assembly on Tuesday before meeting with South Korean president Moon Jae-in and Japanese prime minister Shinzo Abe on Thursday to try to work out a strategy to deal with North Korea.
Trump spoke with his South Korean counterpart on Saturday night and pair agreed to exert “stronger pressure” on Pyongyang.
The White House said Trump and Moon had committed to “take steps to strengthen deterrence and defence capabilities” of South Korea, offering no details of how it might do so.
Trump tweeted to tell his followers about his call with the South Korean president, adopting a new nickname for Kim Jong-un in the process.
He tweeted: “I spoke with President Moon of South Korea last night. Asked him how Rocket Man is doing. Long gas lines forming in North Korea. Too bad!”
The UN Security Council imposed a raft of new sanctions on North Korea last week but they will only be effective if China and Russia fully implement them.
Beijing is believed to be growing increasingly frustrated with Pyongyang after Kim Jong-un’s regime, which used to notify China ahead of weapon tests, did not issue a warning before its nuclear blast earlier this month.
North Korea expert Zhao Tong said many Chinese people “now see North Korea as a major liability”.
He added: “And it appears North Korea doesn’t mind annoying Beijing.”
Defiant North Korea has fired 22 missiles during 15 tests since February, despite international calls for the country to stop its weapon operations.
A hydrogen bomb was detonated on September 3 in the regime’s most powerful nuclear test to date.
And the rogue state’s weapon tests have put a strain on China and North Korea – two historical allies.
Chinese Foreign Ministry spokesperson Hua Chunying said on Friday: “China is not the focus.
“China is not the driving force behind the escalating situation. And China is not the key to resolving the issue.”