July 20 (UPI) — Secretary of State Mike Pompeo and U.S. Ambassador to the United Nations Nikki Haley on Friday warned China and Russia against easing sanctions pressure on North Korea by allowing the country to circumvent caps on oil imports.

U.S. officials said Pyongyang is using illegal ship-to-ship transfers with the two countries to skirt sanctions on refined petroleum. On July 12, Haley’s office submitted a report to the U.N. Security Council’s sanctions committee saying such illegal transfers likely happened 89 times between Jan. 1 and May 30.

“Even if each of these tankers delivered only one-third of its listed capacity, the associated volume would be above the … annual quota of 500,000 barrels per annum,” the report said according to the Washington Examiner.

The report called for the oil transfers to stop.

Pompeo said Friday that by easing pressure on the sanctions against North Korea, it de-incentivizes the country from giving up its nuclear weapons program.

“It will take full enforcement of sanctions for us to get there,” he said during a joint news conference with Haley at U.N. headquarters in New York City.

Haley echoed his statements, urging the U.N. Security Council to “hold tight.”

“We can’t do one thing until we see North Korea respond to their promise to denuclearize,” she said.