He said "good progress" has been made but it would be "hard work" to get a deal by his February deadline.
German Chancellor Angela Merkel said the leaders "all want a compromise".
BBC report here.
The President of the European Council, Donald Tusk, recognised publicly before this week's meeting that the EU must confront difficult issues on freedom of movement and that there is a real possibility of Britain voting to leave if no effort is made to meet British concerns. Report on his speech here.
The Economist thinks that the Prime Minister is playing a bad hand well:
Clearly there is masses of spin from every side. One group of BREXIT supporters are trying to rubbish any possible deal in advance and constantly suggesting that Cameron is hardly asking for anything.
Another group of BREXIT supporters are suggesting that David Cameron is deliberately making progress in the negotiations look difficult so that it will look like a triumph if he does deliver anything significant.
Meanwhile all sorts of polling evidence and other indications of how the campaign might go are coming out.
Lord Ashcroft has released a major poll which asks people not whether they intend to vote "Leave" or "Remain" but to pick a percentage from 0% (certain to vote Remain) to 100% (certain to vote Leave) with 50% meaning you are equally likely to vote either way.
A superficial reading appears to show "Leave" with the advantage because their support is more solid. (Big surprise!)
However, although the "mean" level of support is a little over 51% (reflecting this, and suggesting a slight advantage for "Leave" the really key point is that the MEDIAN voter - the person who has half the country more pro Brexit and half more pro staying than him or her - is one of the 14% who answered "50%".
In other words, it is clear from the number of undecided voters that there is everything to play for.
The full results of the poll can be read on Lord Ashcoft's site at http://lordashcroftpolls.com/
The fact that so many people are undecided means that this sort of infighting by UKIP and between the two rival "leave" campaigns could be disastrous to the cause of those who want to quit the EU:
1) UK's only MP calls on Nigel Farage to step down as leader
2) "Obvious from @Nigel_Farage just now when I was on @daily_politics that @ukip is toying with withdrawing the whip from @DouglasCarswell"
— Daniel Finkelstein (@Dannythefink) December 18, 2015"
James Forsythe in the Spectator writes that "Vote Leave could be formidable" but prominent supporters of Brexit told him privately that despite the polls, they think that in reality "Leave" is well behind. You can read his article at
My key take out, as explained above is that there is absolutely everything to play for. This really could go either way.