The export of coal, ore and other raw materials to China is one of North Korea's few sources of cash.
After the latest North Korea launch prohibited by United Nations resolutions on July 28, US Ambassador Nikki Haley said she didn't want to conduct an emergency Council meeting because she was exhausted of such sessions that were just full of words.
The UN Security Council on Saturday unanimously backed a US-drafted resolution that significantly strengthened sanctions on North Korea, imposing a ban on exports aimed at depriving Pyongyang of $1 billion in annual revenue. "North Korea should forgo the path of provocation, forgo the path of further escalation".
"We should not fool ourselves into thinking we have solved the problem", Haley told the council before the vote.
US Ambassador Nikki Haley said the stiffer measures brought the penalty imposed on North Korea for its ballistic missile tests "to a whole new level" and that the council had put leader Kim Jong-Un "on notice".
"To have China stand with us, along with Japan and (South Korea) and the rest of the global community telling North Korea to do this, it's pretty impactful", Haley said.
Estimates say that North Korea exports about $3bn worth of goods each year - and the sanctions could eliminate $1bn of that trade.
The draft resolution also calls for an end to joint ventures with North Korea and any new investments with existing joint operations.
China and Russian Federation had resisted the United States push, arguing that dialogue with North Korea was the way to persuade Pyongyang to halt its military programs.
Washington has also said United States nationals who are resident in the country must have left by this date.
It also prohibits countries from increasing the current numbers of North Korean laborers working overseas, bans new joint ventures with North Korea and any new investment in current joint ventures. "This was a gut punch to North Korea".
China's ambassador, Liu Jieyi, said the resolution showed that the world was "united in its position regarding the nuclear position on the Korean peninsula".
Through the planned ban, the North is expected to lose $400 million in its annual export revenue, the Voice of America (VOA) quoted a United Nations diplomat as saying.
"He [Trump] has told me that, I believe him, and if I were China I would believe him too, and do something about it", he said in an interview with NBC's Today programme.
"If there is an opportunity that naturally occurs, we should talk", Kang Kyung-Wha said as she landed in Manila on Saturday, according to South Korea´s Yonhap news agency.