Delegates from nearly 200 countries continue to work Saturday at a climate conference in South Africa, trying to reach an agreement on how to fight global warming.

Representatives worked long into the night, well past Friday's scheduled end to the two-week U.N. Framework Convention on Climate Change in Durban.

Negotiators are concerned they will not have enough time to format all concerns into a European Union proposal to create a binding pact to fight global warming. Observers says the worlds biggest polluters, including the U.S., China, and India have not yet agreed on the proposal.

The Europeans won critical support Thursday from an alliance of the world's poorest countries and small island nations. The EU has indicated that the world's biggest polluters have been slowing down the pace of the negotiations.

The EU plan sets a 2015 target date for an agreement that would bind all nations to legal commitments to tackle greenhouse gases. The EU has said it will not renew its emissions reductions pledges under the Kyoto Protocol unless all countries are committed to controlling their emissions.

The United States has previously said it will only pledge binding cuts if all major polluters make comparable commitments. China and India have said their level of cuts should be less than those of developed nations. None of those three countries is bound by the Kyoto Protocol.