Beijing–The US climate envoy said on Friday that he had held constructive talks with China this week but indicated that no breakthroughs were made in their dispute over fraught climate change negotiations.
Todd Stern, who met Chinese climate negotiator Xie Zhenhua, also said the prospects of a substantive new deal to address global warming being reached at a world climate gathering in Mexico starting next month were unclear.
"This could go either way," Stern told reporters.
China and the United States clashed at a UN climate gathering earlier this month in the Chinese city of Tianjin, accusing each other of blocking progress ahead of the summit in the Mexican resort of Cancun.
The United States wants China, the world's largest source of the greenhouse gases blamed for climate change, to commit to curbing carbon emissions and wants developing countries to agree to more scrutiny of their climate claims.
China has lashed out at the pressure for outside verification, saying it was a US attempt to divert attention from the fact the United States has so far failed to get emissions-cutting legislation through Congress.
Stern said he offered no new proposals in his talks in China.
"There's nothing new but we are standing behind what we have already done," he said.
The administration of US President Barack Obama has pledged to cut emissions by 17 percent from 2005 levels by 2020.
The long-running UN negotiations are aimed at eventually securing a binding global treaty on how to limit and cope with climate change.
This would replace the Kyoto Protocol, which expires at the end of 2012 and aims to keep global warming below the threshold that scientists warn will trigger catastrophic damage to the world's climate system.
