US Secretary of State Rex Tillerson told Russia and China to reconsider their allegiances over North Korea on Friday, accusing them of flouting Security Council sanctions.
Tillerson represented the US in the discussion chaired by Japanese Foreign Minister Taro Kono. Pyongyang's ambassador Ja Song Nam is also due to speak.
"Continuing to allow North Korean labourers to toil in slave-like conditions" and send back currency to Pyongyang calls into question Russia's commitment to ending the nuclear crisis, Tillerson said.
The top US diplomat also said that Chinese crude oil that "flows" into the reclusive nation is undermining the international efforts.
Tillerson called on countries that have not implemented sanctions or have been slow to do so to "consider your interests, allegiances and values in the face of this grave threat."
"We will not accept a nuclear North Korea," Tillerson said, adding that all options remain on the table.
But, Tillerson said, "North Korea must earn its way back to the table."
The pressure campaign will continue until nuclear disarmament is achieved, he said.
"In the meantime we will keep channels of communication open."
The meeting rounds off a North Korea-heavy week at the United Nations, with the Security Council discussing human rights in the reclusive nation in a session on Monday morning and hearing from women who were forcibly repatriated by Kim Jong Un's regime in a US-led side event in the afternoon.
On Tuesday, Jeffrey Feltman, the highest-ranking UN official to visit the reclusive communist state since February 2010, briefed council members on his four-day trip to Pyongyang last week, where he had a series of meetings with Foreign Minister Ri Yong Ho and his deputy Pak Myong Guk.
Feltman said he emphasized the importance of reopening channels of communication and told reporters "we've left the door ajar" for negotiations to stop rising tensions on the Korean Peninsula and between Washington and Pyongyang.
