China, which announced a target for reducing the rate of growth of its greenhouse gas emission, has rejected any kind of international monitoring while the United States says the lack of stringent verification of China's actions could be a deal-breaker, The New York Times reported Tuesday.
The stalemate occurred Monday as the U.N.-sponsored climate change gathering in Copenhagen, Denmark, moved into its second and final week.
"I think there's no doubt that China, when it says 40 (percent) to 45 percent reduction in energy intensity, is serious about that," Ed Miliband, the British secretary of state for energy and climate change, told the Times.
The more challenging quest was finding a way that China can prove it is reducing its emissions by the amount it claims, Miliband said.
He Yafei, the Chinese vice foreign minister, said China's laws would guarantee compliance, calling the issue "a matter of principle."
Todd Stern, the lead U.S. negotiator at the conference, said Monday overall progress was made to reach an agreement.
"In any big and complicated negotiation, and this may be the biggest and most complicated ever, it never goes smoothly," he said. "It never goes as planned. There's always bumps."
U.S. President Obama and other world leaders said they hoped to strike an interim agreement while in Copenhagen, but a binding international pact likely won't be completed until next year.