Irish foreign minister, Simon Coveney was out with some Brexit-related comments in the last hour and said that a Brexit deal is difficult but still possible at the summit.
Additional quotes:
Brexit negotiating teams made progress but slow.
Need watertight legal text on Brexit.
Today is a key day to finalize the Brexit text.
It would be much cleaner if a deal is struck this week.
Brexit talks can move beyond the summit and into next week.
There is no plan for an emergency Brexit summit next week.