COPENHAGEN - President Obama said yesterday that the United States, China and several other countries reached a "unprecedented breakthrough" to curb greenhouse-gas emissions - including a mechanism to verify compliance - after a frenzied day of diplomacy at the U.N. climate talks.

The agreement, which also includes the developing nations of India, South Africa and Brazil, requires each country to list the actions it will take to cut global-warming pollution by specific amounts, a senior Obama administration official said.

The official described the deal on the condition of anonymity because specific details had not been announced.

The deal reiterates a goal that eight leading industrialized nations set earlier this year on long-term emission cuts and provides a mechanism to help poor countries prepare for climate change.

A European Union official said an overall agreement involving those nations not included in the deal that Obama announced was still being negotiated.