UN climate talks in China have ended without a major breakthrough and with angry words about the US from Beijing.
At the talks in Tianjin, China blamed the US for failing to meet its responsibilities to cut emissions and for trying to overturn UN principles.
The US accused China of refusing to have its voluntary energy savings verified internationally.
But there was some progress toward the next round of climate talks in Mexico in November.
There are hopes that the meeting in Cancun could agree details of a fund to transfer $100bn (£63bn) a year from rich countries to help poor nations cope with the projected consequences of climate change.
That sum is described by developing nations as substantial but inadequate.
It has been the old deadlock in the northern Chinese city of Tianjin during the week-long talks.
China feels unfairly criticised by the US.
On Saturday, one of the Chinese climate negotiators reportedly accused the US of behaving like a preening pig, complaining about Beijing when Washington had done so little itself.
The head of the US delegation, Jonathan Pershing, was more diplomatic.
But he said that there could be no US signature on any binding deal that did not also bind China - America's superpower rival.
Despite general frustration at the superpower stand-off, there was some progress in Tianjin.
If the $100bn fund can be agreed in Cancun, it will prove that these talks are not dead.
If even this part of the package falls, diplomats in Tianjin are warning it will threaten the future of multilateral action between nations of the world on anything.