The United Nations has reportedly lifted sanctions on four container ships previously blacklisted for links to illegal arms trade by Pyongyang.The US permanent mission to the UN informed several US embassies of the decision via a diplomatic cable issued on February 16, Reuters quoted unnamed officials as saying on Tuesday. The ships were among 31 vessels banned by UN Security Council(UNSC) on March 2, because of ties to Ocean Maritime Management(OMM), a North Korean shipping firm suspected of transporting arms and other illicit goods for the secretive state. The cable showed talks between American and Chinese officials in the lead up to the bans removal, with Beijing securing assurances that the vessels would not be operated by North Korean crews. “We discovered that they are not OMM ships, ” said Liu Jieyi, the Chinese ambassador to the UN. Among the four ships was the Jin Teng, a cargo ship detained by the Philippines shortly after the sanctions took effect. A US official welcomed the move, saying it showed a “productive working relationship with China” on North Korea while proving the “instant real - world effects” of the sanctions regime. The move comes weeks after the US and China formed a front in the UN to slap new sanctions on Pyongyang following its fourth nuclear test in January and an alleged satellite launch the next month. The 15 - member UNSC has confirmed the act and will make an official announcement in a press release, according to Reuters. Both the US mission at the UN and the US Treasury Department which observes the implementation of the sanctions refused to comment on the matter. Last week, US President Barack Obama signed a new executive order that tightens the US trade embargo on North Korea over the country’s recent nuclear and missile tests. However, North Korea says it will not relinquish its nuclear deterrence unless Washington ends its hostile policy toward Pyongyang and dissolves its military command in South Korea.