WASHINGTON • US President Donald Trump has dismissed a Chinese diplomatic effort to rein in North Korea's weapons programme as a failure, while Secretary of State Rex Tillerson said Beijing was doing a lot, but could do more to limit oil supplies to Pyongyang.
In a tweet on Thursday, Mr Trump delivered another insulting barb against North Korean leader Kim Jong Un, whom he called "Little Rocket Man" and a "sick puppy" after North Korea test-fired its most advanced missile to date on Wednesday.
Mr Trump's tweets further inflamed tensions reignited this week after North Korea said it had successfully tested a new intercontinental ballistic missile in a "breakthrough" that put the US mainland within range of its nuclear weapons.
"The Chinese envoy, who just returned from North Korea, seems to have had no impact on Little Rocket Man," Mr Trump said on Twitter, a day after speaking with Chinese President Xi Jinping and reiterating his call for Beijing to use its leverage against North Korea.
Mr Tillerson on Thursday welcomed Chinese efforts on North Korea, but said Beijing could do more to limit its oil exports to the country.
"The Chinese are doing a lot. We do think they could do more with the oil. We're really asking them to please restrain more of the oil, not cut it off completely," Mr Tillerson said at the State Department. China is North Korea's neighbour and its sole major trading partner.
While Mr Trump has been bellicose at times in rhetoric towards North Korea, Mr Tillerson has persistently held out hopes for a return to dialogue if North Korea shows it is willing to give up its nuclear weapons programme.
However, Mr Tillerson may not remain in his job for long, with disagreements with Mr Trump over North Korea being one factor.
In spite of Mr Trump's rhetoric and warnings that all options, including military ones, are on the table in dealing with North Korea, his administration has stressed that it favours a diplomatic solution to the crisis.
United States Defence Secretary James Mattis said he still had confidence in diplomatic efforts on North Korea and that the US would be "unrelenting" in working through the United Nations.
Mr Trump has pledged more sanctions in response to the latest test and, at an emergency UN Security Council meeting late on Wednesday, the US warned that North Korea's leadership would be "utterly destroyed" if war were to break out.
Previous US administrations have failed to stop North Korea from developing nuclear weapons and a sophisticated missile programme.
Mr Trump, who has previously said the US would "totally destroy" North Korea if necessary to protect itself and its allies from the nuclear threat, has also struggled to contain Pyongyang since taking office in January.