By Michael Hernandez

WASHINGTON

The U.S. called on the UN Security Council on Friday to maintain sanctions pressure on North Korea after China and Russia delayed additional measures to halt Pyongyang’s oil imports.

Addressing reporters after meetings at the UN's New York headquarters, Secretary of State Mike Pompeo said illegal ship-to-ship transfers "are the most prominent means" Pyongyang is using to evade the international body's oil sanctions.

The council moved in December to cap the North's refined oil imports to just 500,000 barrels per year

The North has conducted at least 89 such transfers in the first five months of this year alone, according to Pompeo.

“Enforcement of sanctions is a continuing process," he said, stressing "strict enforcement of sanctions is critical" to the denuclearization of the Korean peninsula.

Pompeo urged the North to take "concrete actions" toward that goal, and said North Korean leader Kim Jong-un has committed to the country's full denuclearization during meetings with President Donald Trump and South Korean President Moon Jae-in.

Russia and China moved Thursday to halt progress on additional measures within the Security Council to fully curtail the North's oil imports, with Moscow saying it needed more information on the illicit efforts before it could move forward.

China backed Russia's effort citing the same justification.

But Nikki Haley, the U.S.'s UN envoy, disputed the notion more information is needed, saying the U.S. has photographic evidence to support its claim while urging the council to "hold the line" in order to secure the North's denuclearization through ongoing negotiations.

“The best way we can support those talks is to not loosen the sanctions,” she said.

She warned that "certain countries" are seeking to circumvent standing sanctions by seeking waivers or the watering down of the economic penalties.

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

A major sticking point in ongoing talks is Washington's plan for North Korea's complete, verifiable and irreversible denuclearization.

Pyongyang has consistently demanded a more gradual process based on developing mutual trust.