Russia defended its use of North Korean laborers and told Secretary of State Rex Tillerson at a Friday United Nations Security Council meeting that the workers aren't treated like slaves.

“I'd like to say to the distinguished secretary of state that the North Korean workers aren't working in Russia in 'slave-like conditions,’” said Vassily Nebenzia, the Russian envoy to the United Nations.

That was a direct response to Tillerson’s comments minutes earlier, when the top U.S. diplomat traveled to New York to deliver an explicit rebuke of China and Russia. Tillerson urged both countries to cut ties with North Korea, citing the need to pressure the regime into abandoning its nuclear weapons program before the U.S. is forced to take military action.

One of the cuts Tillerson urged was an end to allowing North Koreans to work in their countries.

“Continuing to allow North Korean laborers to toil in slave-like conditions inside Russia in exchange for wages used to fund nuclear weapons programs calls into question Russia’s dedication as a partner for peace,” Tilllerson said. “Similarly, as Chinese crude oil flows to North Korean refineries, the United States questions China’s commitment to solving an issue that has serious implications for the security of its own citizens.”

Nebenzia rejected that charge. “They're working on the basis of an intergovernmental agreement with the [regime] which guarantees their rights,” he told Tillerson.

State Department human trafficking monitors faulted both Russia and North Korea for the deals, as the laborers “do not have a choice in the work the government assigns them” and see most of their wages confiscated.

“[The Russian] government maintained, and recently expanded, bilateral contracts with the Democratic People’s Republic of Korea (DPRK or North Korea) under which the DPRK operated labor camps on Russian soil and subjected thousands of North Korean workers to forced labor,” the 2017 State Department report on human trafficking says. “Authorities routinely detained and deported potential forced labor victims without screening for signs of exploitation, and prosecuted victims forced into prostitution for prostitution offenses.”

As Nebenzia defended the system, he also complained that the U.S. is causing suffering in North Korea by pursuing an aggressive sanctions policy against “civilian sectors” that don’t have obvious ties to the nuclear weapons and ballistic missile programs.

“These sanctions are the reason for a serious worsening in the living conditions of the population,” he said. “Therefore, unilateral limits which circumvent or add to what's being done through the Security Council undermine the effective implementation of the Security Council's decisions on the political settlement of the situation on the Korean Peninsula, not to mention that damage that is being done to the legal interests of third countries.”

Tillerson wants China to impose an oil embargo on North Korea, even though China and Russia prevented the UN from mandating such a restriction in September. “The last time the North Koreans came to the table, it was because China cut the oil off,” Tillerson said Tuesday. “Three days later, the North Koreans were at the table talking.”