Washington: US President Donald Trump has issued a stern warning to North Korean leader Kim Jong-Un, saying he will "truly regret" any hostile acts against Guam or any other American territory.

"If he (Kim Jong-Un) utters one threat, in the form of an overt threat, which by the way he has been uttering for years, and his family has been uttering for years, or if he does anything with respect to Guam, or any place else that's an American territory or an American ally, he will truly regret it and he will regret it fast," Trump told reporters at his summer vacation home in Bedminster, New Jersey on Friday.

Earlier in the day, the US President told his 35.5 million followers on Twitter that military solutions against the nuclear-armed North Korean regime were "locked and loaded" for use if Pyongyang acted "unwisely".

Military solutions are now fully in place,locked and loaded,should North Korea act unwisely. Hopefully Kim Jong Un will find another path! — Donald J. Trump (@realDonaldTrump) August 11, 2017

"Military solutions are now fully in place, locked and loaded, should North Korea act unwisely. Hopefully (North Korean leader) Kim Jong Un will find another path!" he wrote in a tweet.

"USAF B-1B Lancer bombers on Guam stand ready to fulfil USFK's fight tonight mission if called upon to do so," the Pacific Command said in a tweet.

Trump defended his stand against North Korea and claimed that Americans are happy with his remarks.

"My critics are only saying that because it's me. If somebody else uttered the exact same words that I uttered, they'd say what a great statement, what a wonderful statement," he said.

"But I will tell you, we have tens of millions of people in this country that are so happy with what I am saying because they say finally we have a president that's sticking up for our nation and frankly, sticking up for our friends and our allies. This man will not get away with what he is doing, believe me," he added.

Talking about his tweet on the military solutions in Guam, Trump said, "I think it's pretty obvious. We are looking at that very carefully and I hope they are going to fully understand the gravity of what I said, and what I said is what I mean."

"So hopefully they (North Korea) will understand exactly what I said and the meaning of those words. Those words are very, very easy to understand," the president said.

He said he does not want to talk about back channel talks with North Koreans as being reported by some media outlets.

"We don't want to talk about progress, we don't want to talk about back channels. We want to talk about a country that has misbehaved for many many years, decades actually, through numerous administrations and they didn't want to take on the issue and I had no choice but to take it on, and I'm taking it on," he said.

"We will either be very, very successful quickly or we're going to be very, very successful in a different way, quickly," he added.