The United Nations Security Council has unanimously approved the toughest sanctions against North Korea in two decades, though some critics say they still do not go far enough and will be hard to police.

The fresh sanctions, approved Wednesday in New York, come on the heels of the hermit kingdom's recent nuclear test and rocket launch, which angered the international community.

The move highlighted closer cooperation between the United States and China after weeks of negotiations, but its efficacy hinges on whether and how much China, Pyongyang's biggest economic partner, and Russia would enforce it.