Prime Minister David Cameron on Friday said he had still not reached a deal with EU counterparts to try and keep Britain in the bloc as a crunch Brexit summit went into a second day.

"I was here until five o'clock in the morning... we made some progress but there is still no deal," Cameron said as he arrived at the EU headquarters in Brussels.

"As I have said, I would only do a deal if we get what we need, so I am going to get back in there."