China has tightened restrictions on trade with North Korea under UN nuclear sanctions, imposing a cap on oil supplies to the North and banning imports of its steel and other goods.
The measures follow increased Security Council penalties imposed following the North’s ballistic missile test on November 29.
The Chinese commerce ministry said Beijing will limit exports of crude oil and refined petroleum to the North and ban outright sales of steel and industrial machinery.
Imports of North Korean food, machinery and some other goods are banned.
China is the North’s main trading partner and energy supplier, making its enforcement measures critical to the success of sanctions.
Despite the loss of almost all trade, the impoverished North has pressed ahead with weapons development that the North’s leader Kim Jong Un’s regime sees as necessary for its survival in the face of US pressure.
China has steadily increased economic pressure on Pyongyang while calling for dialogue to defuse the increasingly acrimonious dispute with US president Donald Trump’s government.
A foreign ministry spokesman applauded news of possible talks between the North and South Korea’s government.
Geng Shuang said: "We welcome the recent positive turn of events in the peninsular situation."
He expressed hope "all relevant parties" would take advantage of the upcoming Winter Olympics in Pyeongchang, South Korea, to "bring the issue back to the correct track of peaceful settlement through dialogue and consultation".
In the same briefing, Mr Geng said China’s government would "deal seriously" with violators of UN sanctions on North Korea after a South Korean newspaper said Chinese-owned ships registered abroad regularly traded oil to the North.
Analysts see North Korea’s need for Chinese oil as the most powerful economic leverage against Pyongyang.
But Chinese leaders have warned against taking drastic measures that might destabilise Mr Kim’s government or send a wave of refugees into China.
Chinese leaders have resisted previous US demands for an outright oil embargo but went along with the latest limits.
Under the new restrictions, Chinese companies will be allowed to export no more than four million barrels of oil and 500,000 barrels of refined petroleum products per year.
They are barred from supplying the North’s military or weapons programmes.
The new measures also ban sales of steel, industrial machinery and vehicles. The commerce ministry said imports of North Korean food, machinery and some other goods will be banned.
In September, North Korean businesses in China were ordered to close by this month, cutting off an important supply of foreign currency.
Most North Koreans who work in factories and other Chinese businesses have been sent home.
Chinese officials complain their country bears the cost of enforcement, which they said has hurt businesses in its north-east.
Previous sanctions banned sales of natural gas to North Korea and purchases of the North’s textile exports, another key revenue source.
China also has banned imports of North Korean coal, iron and lead ore and seafood since early September.