Barack Obama phoned the Chinese leader, Xi Jinping, in a last ditch effort to thrash out a climate change agreement that can be unveiled at the UN climate talks in Paris on Saturday.
As the negotiations ran into overtime - something that has happened at virtually every meeting of the last 20 years - Laurent Fabius, the French foreign minister called for a cooling off period to allow more high level lobbying behind closed doors. Fabius put off planned public plenary sessions, which risk being volatile, and gave the floor over to closed meetings in a last push for an agreement, Reuters reported.
The French hosts were still insisting they expected the final draft text - the skeleton of a climate change agreement - to be ready by Saturday when more peaceful protests are planned by climate activists across Paris. Civil society groups will hand out thousands of red tulips to represent red lines they say should not be crossed, and hold a rally under the Eiffel Tower if and when a deal is reached.
Even with Obama's efforts to call in political favours with the Chinese president though, sharp divisions remain between the US, India and China.
Ban Ki-moon, the United Nations secretary general, said the talks were the most complicated and difficult negotiations he had ever been involved in.
"I have been attending many difficult multilateral negotiations, but by any standard, this negotiation is most complicated, most difficult, but most important for humanity. We have just very limited hours remaining," Ban told reporters.