Story highlights Beijing is Pyongyang's biggest trade partner

The UN Security Council imposed toughest sanctions yet on N Korea in November 2016

Beijing (CNN) China says it will halt all coal imports from North Korea, starting Sunday and for the rest of 2017, amid growing tensions on the Korean Peninsula following Pyongyang's most recent missile test last week.

China's Ministry of Commerce, in a public notice jointly issued with the country's customs agency Saturday, said the decision was made to comply with a UN Security Council resolution that China helped draft and pass last November.

Resolution 2321 imposed some of the toughest sanctions yet against the North Korean regime, after it disregarded an earlier UN ban to test what it said was a nuclear warhead in September 2016.

"Imports of coal produced in North Korea -- including shipments already declared to the customs but yet to be released -- will be suspended for the remainder of this year," said the statement posted on the ministry's website.

Coal is North Korea's main export and an important source of foreign currencies for its fragile economy. Most of North Korea's exported coal is shipped to China, its only major ally on the global stage.