The United States is seeking to have the United Nations ban 33 vessels from ports worldwide and blacklist 27 shipping businesses for helping North Korea circumvent sanctions. The US request to a UN sanctions committee, came as President Donald Trump announced Friday the "heaviest sanctions ever" on North Korea over its nuclear and ballistic missile tests. Japan joined the United States in supporting the request concerning three of the 33 vessels for carrying out ship-to-ship transfers of oil destined for North Korea in violation of UN resolutions. Council members have until Friday at 3:00 pm to raise objections to the proposed sanctions. The measures will come into effect if none of the council members, including the North's ally China, block the request. Only eight vessels have so far been banned from ports for sanctions-busting and the US request would significantly expand the blacklist in a bid to cripple North Korea's maritime network. Last year, the Security Council adopted a series of resolutions to ban North Korean exports of commodities in a bid to cut off revenue to North Korea's military programs. The measures severely restrict deliveries of oil and refined petroleum products to North Korea, but a recent report by a UN panel of experts found that Pyongyang was flouting sanctions. North Korea earned $200 million in revenue last year from exports of coal, iron, steel and other banned commodities, the report said. The United States and Japan are strong backers of sanctions as a way to pressure Pyongyang to come to the negotiating table and end its drive to develop nuclear weapons.