Trump ramps up threats to N Korea, says 'fire and fury' wasn't tough enough

US President Donald Trump has issued fresh warnings to North Korea, saying things will happen to the country like it "never thought possible" if Pyongyang thinks about attacking America or any of its allies.

Referring to his Tuesday's statement that North Korean threat to the US will be met with "fire and fury", he said the message wasn't tough enough and it's time to act for the people of America.

"It's the first time they've heard it like they heard it. Frankly, the people that were questioning that statement, was it too tough, maybe it wasn't tough enough," Trump told reporters at his summer vacation home at Bedminster in New Jersey yesterday.

"They've been doing this to our country for a long time, for many years, and it's about time that somebody stuck up for the people of this country and for the people of other countries. So, if anything, maybe that statement wasn't tough enough," he added.

The president was responding to a question on Tuesday's remarks, which has attracted criticism from traditional foreign policy experts and Democratic lawmakers.

"We are backed 100 percent by our military. We are backed by everybody.. We're backed by many other leaders. I noticed that many senators and others, today came out very much in favour of what I said. But, if anything, that statement may not be tough enough," Trump said.

"The people of this country should be very comfortable, and I will tell you this, if North Korea does anything in terms of even thinking about attack on anybody that we love or we represent or our allies or us, they can be very, very nervous," Trump said.

"They should be very nervous, because things will happen to them like they never thought possible. He (Kim Jong-Un) has been pushing the world around for a long time. I have great respect for what China and what Russia did, and we got a 15- to-nothing vote," he added.

However, the president did not divulge any details as to how the US is planning to tackle the North Korean threat.

"We don't talk about that. I never do. I'm not like the other administration that would say. We're going into Mosul in four months, I don't talk about it. We'll see what happens.

"But I can tell you that what they (North Korea) have been doing and what they've been getting away with is a tragedy. It can't be allowed," he said.

Trump also praised his United Nations Ambassador Nikki Haley on being successful in getting the Security Council sanctions on the Asian country.

"Nikki Haley did a great job. We all did a great job. But I have great respect for what they did. I have great respect for the 15-to-nothing. But, probably, it will not be as effective as a lot of people think it can be, unfortunately," he said.

Talking about China, Trump said the communist nation can do a lot more in helping the US handle the threat from the Kim Jong-Un regime.

"We have trade with China. We lose hundreds of billions of dollars a year on trade with China. They know how I feel. It's not going to continue like that. But, if China helps us, I feel a lot differently toward trade, a lot differently towards trade," he said.

In yet another warning to North Korea, the US president said the country better get its act together or they are "going to be in trouble like few nations ever have been in trouble in this world", while stressing that the US and allies are safe.