Russia and China on Tuesday delayed a U.S. request for a U.N. Security Council sanctions committee to demand an immediate halt to deliveries of refined petroleum to North Korea over accusations Pyongyang violated a U.N. cap, diplomats said.

The United States, backed by dozens of allies, told the committee last week that there had been at least 79 illegal deliveries of fuel in 2019 – mainly through transfers between ships at sea – and concluded that North Korea had breached an annual U.N. cap of 500,000 barrels imposed in December 2017.

North Korea’s U.N. mission has not responded to a request for comment on the accusations.

Washington wanted the 15-member U.N. Security Council North Korea sanctions committee to issue a demand for an immediate halt to deliveries of refined petroleum to North Korea.

But the committee operates by consensus and on Tuesday Pyongyang allies Russia and China delayed Washington’s request for action by putting a so-called “hold” on it, diplomats said. They told the committee they believed the current situation was still in line with the relevant Security Council resolution, diplomats said.

“We need more details as usual because they provided generalized information,” Russian U.N. Ambassador Vassily Nebenzia told Reuters.

China and Russia placed a similar U.S. request in limbo a year ago, saying they needed more details on Washington’s accusation then of 89 illicit fuel imports by North Korea in the first five months of 2018.

“The restriction on the DPRK’s refined petroleum imports is critical to maintaining pressure on the DPRK, including those parties responsible for its WMD (weapons of mass destruction) programme, to achieve the final, fully verified denuclearisation of the DPRK,” read last week’s U.S. complaint, seen by Reuters.

North Korea is officially known as the Democratic People’s Republic of Korea (DPRK).

The U.N. Security Council has unanimously boosted sanctions on North Korea since 2006 in a bid to choke funding for Pyongyang’s nuclear and ballistic missile programs, banning exports including coal, iron, lead, textiles and seafood, and capping imports of crude oil and refined petroleum products.

The U.S. accusation coincided last week with U.S. President Donald Trump announcing he had received a “beautiful” letter from North Korean leader Kim Jong Un. Washington is seeking to rebuild momentum in stalled talks with Pyongyang, aimed at getting North Korea to dismantle its nuclear weapons programme.

Under U.N. sanctions, countries are required to report to the Security Council North Korea sanctions committee monthly sales of refined petroleum to North Korea. According to the committee website, only Russia and China have reported legitimate sales to Pyongyang during the past two years.

While the latest U.S. complaint that North Korea has breached the U.N. cap does not name who it believes is supplying refined petroleum for the transfers at sea, former U.S. Ambassador to the U.N. Nikki Haley accused Russia in September of “cheating” U.N. sanctions on North Korea.

Russia’s Ministry of Foreign Affairs rejected the U.S. accusations.

Reuters has also reported that Russian tankers had supplied fuel to North Korea by transferring cargoes at sea.