Donald Trump has lashed out at North Korea on Friday, accusing the rogue state of "behaving badly" and "playing" the US, shortly after his secretary of state, Rex Tillerson, said military action was "on the table."
In what is likely to exacerbate the president's strained relationship with Beijing, Mr Trump added in a tweet that "China has done little to help."
It comes after Rex Tillerson, Washington’s top diplomat, said the days of approaching the North Korean issue with "strategic patience" were over.
The US Secretary of State said previous diplomatic efforts to rein in the North had failed, but offered no fresh ideas on how to deal with Pyongyang, which is alarming the world with its nuclear ambitions.
"Certainly we do not want things to get to military conflict, " he said.
"If they elevate the threat of their weapons programme to a level that we believe requires action, then, that option's on the table."
He added that the North “need not fear” the United States, as he began a visit to Asia calling for a “new approach” to the rogue nation.
North Korea is behaving very badly. They have been "playing" the United States for years. China has done little to help!— Donald J. Trump (@realDonaldTrump) March 17, 2017
China said it would welcome fresh ideas on dealing with simmering tensions in North-east Asia, while a North Korean official in Beijing warned that the US and South Korea were taking the region to the “brink of nuclear war”.
Mr Tillerson made his comments after he met with Japanese Foreign Minister Fumio Kishida in Tokyo. "North Korea and its people need not fear the United States or their neighbours in the region who seek only to live in peace with North Korea," he said.
"With this in mind, the United States calls on North Korea to abandon its nuclear and ballistic missile programs and refrain from any further provocation."
Tensions were raised last week after Pyongyang fired four missiles, in an apparent response to joint military exercises by South Korea and the US which began a few days earlier.
Such maneuvers had caused Pyongyang to take “tough measures”, a North Korean diplomat told reporters in Beijing on Thursday.
He said they had bought the Korean peninsula “to the brink of nuclear war”, according to a report by the Global Times newspaper.
North Korea caused international outrage in 2006 when it carried out its first underground atomic test. Four more tests have followed, including two last year.
Tough UN sanctions have failed to deter the North from scrapping its ambitious military program.
Last week the Chinese foreign minister suggested Pyongyang could halt its nuclear plans if the United States and South Korea suspended military activities in the region.
US officials immediately rejected that proposal, and Mr Tillerson called for a fresh outlook during his visit to Japan.
"In the face of the ever-escalating threat it is clear that a new approach is required," Mr Tillerson said. Chinese foreign ministry spokeswoman Hua Chunying said: "If the US or another country has a better plan, a better proposal, they can bring it out.”
Mr Tillerson travels to South Korea on Friday before heading to Beijing at the weekend.
He is expected to urge Chinese officials to exert more pressure on the North, and also lay the groundwork for a visit to the US next month by Xi Jinping, the Chinese president.
Additional reporting by Christine Wei