U.S. Secretary of State Mike Pompeo said Friday that fully enforcing economic sanctions on North Korea is a make-or-break factor in ridding the country of nuclear weapons amid slow progress in negotiations between Washington and Pyongyang.

"The countries of the Security Council are united on the need for final, fully verified denuclearization of North Korea," the chief U.S. diplomat told reporters after his briefing to the U.N. council on the North Korea situation. "Strict enforcement of sanctions is critical to our achieving this goal."

"Members of the U.N. Security Council, and by extension all U.N. member states, have unanimously agreed to fully enforce sanctions on North Korea and we expect them to continue to honor those commitments," he added.

(Mike Pompeo)[Getty/Kyodo]

Pompeo reiterated that North Korea is "illegally smuggling" petroleum products in violation of Security Council sanctions, a day after China and Russia blocked a U.S. bid to halt all deliveries of refined oil products to the country.

"Right now, North Korea is illegally smuggling petroleum products into the country at a level that far exceeds the quotas established by the United Nations. These illegal ship-to-ship transfers are the most prominent means by which this is happening," he said.

Pompeo also called for cracking down on other forms of sanctions evasion including coal exports by sea and overland borders and the presence of guest workers in certain countries.

The United States called last week on all U.N. member countries to refrain from exporting such products to North Korea as it accused Pyongyang of breaching a U.N. sanctions cap on refined petroleum through illicit ship-to-ship transfers.

Washington made the case to the U.N. Security Council's sanctions committee on North Korea at a time when it is seeking to negotiate the denuclearization of the isolated country.

However, China and Russia called Thursday for putting the U.S. request on hold, saying they need more time to consider it, resulting in a postponement of the ban for up to nine months.

"China and Russia blocked it. Now, for China and Russia to block it -- what are they telling us? Are they telling us that they want to continue supplying this oil?" said U.S. Ambassador Nikki Haley, speaking alongside Pompeo.

"They claim they need more information. We don't need any more information. The sanctions committee has what it needs. We all know (violations are) going forward. We put pressure today on China and Russia to abide and be good helpers through this situation and to help us continue with denuclearization," she added.

Last December, the 15-member Security Council capped refined petroleum product exports to North Korea at 500,000 barrels annually, down from 2 million barrels a year, following Pyongyang's test-firing the previous month of a new type of long-range missile.

China and Russia have reported to the committee that they have sold refined petroleum products to North Korea. The document calls for putting an end to the sales and transfers "immediately" since North Korea is believed to have exceeded its annual limit.

Chinese Ambassador Ma Zhaoxu stressed Beijing's commitment to denuclearization of the Korean Peninsula and said China will fully implement the U.N. sanctions on North Korea.

"China is committed to denuclearization...we are committed to peace and stability on the Peninsula," he told reporters. "We will fully implement the (U.N. sanctions) resolutions. Everybody is doing so."

Friday's briefing, jointly carried out by Pompeo and South Korean Foreign Minister Kang Kyung Wha, assembled officials from the 15 council member states plus Japanese U.N. Ambassador Koro Bessho.

Speaking to reporters ahead of the session, Kang said South Korea intends to have the North make good on its promise to abandon all nuclear weapons and existing nuclear programs.

"They have made a clear commitment on complete denuclearization repeatedly and of course very forcefully at the Singapore summit with (U.S.) President (Donald) Trump and we will hold them up to that commitment," she said.

Talks on denuclearization of North Korea have not progressed, despite an apparent easing of tensions since U.S. President Donald Trump met North Korean leader Kim Jong Un in Singapore on June 12.

In a joint statement issued after the first-ever U.S.-North Korea summit, Kim committed to the "complete" denuclearization of the Korean Peninsula while Trump promised to provide security guarantees to Pyongyang.

Earlier this month, however, the North's Foreign Ministry accused Washington of pushing a "unilateral and gangster-like demand for denuclearization," hours after Pompeo said his talks in Pyongyang with Kim Yong Chol, a close aide to leader Kim, were "productive."

While acknowledging the difficulty of achieving denuclearization in North Korea, Pompeo said the U.S. policy toward that goal will be kept intact.

"It will take full enforcement of sanctions for us to get there. It will also take Chairman Kim following through on his personal commitments that he made to President Trump in Singapore," he said, referring to Kim's title in the Workers' Party of Korea, as well as of the North's State Affairs Commission.

"The path ahead is not easy. It will take time. But our hopes for a safer world for all of us and a brighter future for North Korea remains our objective and that hope endures," Pompeo said.