The United Nations Security Council has unanimously imposed its toughest sanctions on North Korea following the country's defiant nuclear tests. Under the new sanctions resolution, Pyongyang will be restricted from exporting more than 7.5 million tonnes of coal next year, a reduction of 62 per cent from last year. <br/><br/>The resolution demands that North Korea abandon all nuclear weapons and existing nuclear programs and takes aim at the state's exports of coal, its top external revenue source.<br/><br/><br/>The resolution, which was passed by a 15-0 vote, was spearheaded by the United States and came after three months of negotiations with fellow veto-wielding council member China.<br/><br/>UN Secretary-General Ban Ki-moon urged all countries to enforce the resolution. He said, the resolution sends an unequivocal message that North Korea must cease further provocative actions and comply fully with its international obligations.<br/><br/>Mr Ban Ki-moon said, he was still committed to sincere dialogue to resolve the nuclear issue and stood by calls to provide humanitarian assistance to ease the suffering of ordinary North Koreans.