|US Secretary of State Mike Pompeo. Yonhap|
Pompeo spoke with Chinese Foreign Minister Wang Yi and exchanged views on ongoing efforts to achieve the "shared goal of the complete, verifiable, and irreversible denuclearization of the Korean Peninsula," the State Department said in a readout.
The top US diplomat said earlier that China appears to have relaxed sanctions enforcement across its border with North Korea from six or 12 months ago.
In the phone call, he "emphasized the continued importance of full enforcement of all relevant UN Security Council resolutions related to North Korea, especially as they relate to North Korea's illegal exports of coal and imports of refined petroleum through UN-prohibited ship-to-ship transfers," the statement said.
China is North Korea's only major ally and trading partner, accounting for about 90 percent of the impoverished nation's external trade.
Last year Beijing backed a series of UN Security Council resolutions sanctioning North Korea for its nuclear weapons and ballistic missile tests.
Pompeo also noted that North Korea has a "bright future" if it denuclearizes.
The secretary is reportedly planning to travel to Pyongyang next week to try to flesh out an agreement signed by US President Donald Trump and North Korean leader Kim Jong-un at their historic summit in Singapore earlier this month.
Kim committed to the "complete denuclearization" of the Korean Peninsula in return for security guarantees from the US.