EU leaders are in Brussels for their final summit of what’s been a tough year.
Among the pressing issues on the agenda – the migration crisis, which threatens security and the passport-free area.
Plans to bring in a new EU Border and Coast Guard will be debated.
Controversially, the body could step in – uninvited – if a member state is seen as losing control of its frontiers.
“We have to analyse the most controversial proposal, the most controversial idea, of the European border guard entering the territory of sovereign states,” said Donald Tusk, European Council President, as he arrived at the summit.
“But Europe cannot remain vulnerable, when Schengen states are not able to effectively protect their borders.”
Also up for discussion in Brussels is Britain’s push for EU reform. Prime Minister David Cameron’s promised a membership referendum by the end of 2017.
“We are not pushing for a deal tonight, but we are pushing for real momentum so that we can get this deal done,” Cameron told reporters.
“So I will be battling hard for Britain right through the night and I think we will get a good deal.”
Britain’s Labour Party leader Jeremy Corbyn, who is also in Brussels, told euronews that Cameron’s push for change boils down to opposition within the ruling Conservatives.
“I am not really sure what he (Cameron) wants to achieve,” he said.
“Because the background to this is not about the negotiations he is conducting here, it is about the arguments within the Conservative party of large numbers of people who don’t want to be in the European Union, don’t want anything to do with Europe at all.”
Boosting the fight against terrorism is also being discussed at the summit, coming in the wake of the Paris attacks, which left 130 people dead.