North Korea Oil Sanctions

"I spoke with President Moon of South Korea last night. Asked him how Rocket Man is doing. Long gas lines forming in North Korea. Too Bad!"
The above is a tweet Donald Trump posted on his Twitter following the new UN sanctions on North Korea, including restricting the oil imports. The sanctions aren't just to be mean, they're in hopes of preventing the development of more nuclear missiles. Secretary Rex Tillerson demanded that China participate and stop exporting oil to North Korea. China refused to stop exporting oil to North Korea, and stated that the US should be doing more to try and peacefully negotiate with North Korea. China's ambassador to the US, Cui Tiankai, said "[the US] should refrain from issuing more threats...[and] do more to find an effective way to resume dialogue and negotiation."