Difficult talks in Peru aimed at reaching a global deal on climate change look set to be extended.
Delegates are hoping to make progress towards a draft document that can be tabled in Paris late next year.
A total of 190 countries are attempting to resolve their differences over how to cut greenhouse gas emissions, and the talks in Lima were due to wrap up on Friday.
But with deep rifts still evident, the negotiations look set to go on into the weekend.
The US Secretary of State earlier gave a warning to the delegates, saying time was running out to reverse what he calls a road “leading to tragedy”.
Demonstrators have also made their voices heard at the summit, calling for more concrete action and less promises from the big polluting countries.
China, the US, the European Union and India are the top emitters.