Mr Trump warned in a recent speech that China could face a “big problem” with US ally Japan over North Korea’s threat of war.
North Korea has persistently threatened a nuclear attack on the United States and in response, the US has warned of military action.
Donald Trump is the first US president to penalise a Chinese bank for helping North Korea dodge United Nations economic sanctions.
But “Nuclear Showdown” author Gordon Chang said Donald Trump’s speech was a “warning to China” and they must understand that Trump will do “everything possible to defend the American people.”
Speaking to Fox News, he said: “This is a reversal of decades of American policy where we restrain the Japanese.
“Now what [Trump is] doing is he’s saying to China ‘Look, I’m going to use the same tactics that you use. You use North Korea as a proxy against us. I’m going to use Japan as a proxy against you’.
“And I think people in Beijing must be pretty nervous right now because that is such a monumental change for us.”
Trump reiterated his support for Japan in a recent speech and said the US ally is a “warrior nation”. He said: “I tell China and I tell everyone else that listens, I mean, you’re gonna have yourself a big problem with Japan pretty soon if you allow this to continue with North Korea.”
In the speech, he said he understood Japan’s concerns over North Korea’s nuclear threat.
North Korea has upped its hostile approach against the US and its Asian allies, sparking fears World War 3 could happen at any moment.
Mr Trump is on a trip to Asia in an effort to create a united front against North Korea and ask Mr Putin to join the leaders of Japan and South Korea in pressing China to do more to stop the hermit nation.
He warned the US and its allies are prepared to defend freedom and that “no dictator” should underestimate US resolve.
During a news conference in Tokyo, Mr Trump said: “Some people said that my rhetoric is very strong but look at what’s happened with very weak rhetoric over the last 25 years. Look where we are now.”