"That would be a pivotal step in the world's effort to stop this global pariah", she said, warning that if Beijing does not act, "we can take the oil situation into our own hands".
North Korea tested a new intercontinental ballistic missile, the Hwasong-15 on November 29, which Pyongyang claims is capable of reaching any target in the continental United States. We do think they could do more with the oil.
While Trump has been bellicose at times in rhetoric toward North Korea, Tillerson has persistently held out hopes for a return to dialogue if North Korea shows it is willing to give up its nuclear weapons program. On Thursday, senior Trump administration officials said the White House was considering a plan to replace Tillerson with Mike Pompeo, the director of the Central Intelligence Agency.
The isolationist state recently tested a new intercontinental ballistic missile that, it claimed, could reach anywhere on the USA mainland.
As Paul Bracken, a professor of political science at Yale, told Business Insider, Trump has "been reasonably effective" in isolating North Korea and rallying support for sanctions internationally.
"Anything beyond that is not the priority at this point", she said, responding to a question on whether regime change was on the administration's agenda after Trump's recent tweets and a speech by U.N. Ambassador Nikki Haley. While Haley remarked that the "North Korean regime will be utterly destroyed" in such a war, she neglected to mention the damage that South Korea, and possibly the U.S., could also face from a North Korean nuclear attack.
The US earlier pressed for a full oil embargo on North Korea after it tested its most powerful nuclear bomb to date in September, but dropped that demand in negotiations on a sanctions resolution with China.
Experts say the height reached by the inter-continental ballistic missile (ICBM) indicates Washington could be within range, although North Korea is yet to prove it has reached its aim of miniaturising a nuclear warhead. The United States, which has 28,500 troops in South Korea as a legacy of the 1950-53 Korean War, denies any such intention.
The US warned North Korea's leadership will be "utterly destroyed" if war breaks out but its call for nations to cut ties with Pyongyang was rejected by Moscow while Beijing sidestepped talk of an oil embargo.
The US has repeatedly said that it will not accept North Korea as a nuclear power and that it will consider military intervention to stop it.