Denmark holds referendum on relationship with EU
Danes are going to the polls in a referendum on whether to adopt EU justice and policing laws, in a vote overshadowed by the Paris attacks.
The result is expected to be evenly poised between the Yes and No camps.
Denmark's centre-right government, backed by the opposition, wants to abandon some Danish opt-outs from EU home affairs legislation which were secured in 1993.
They say a No vote will mean losing membership of the Europol crime agency.
But the anti-immigration Danish People's Party (DPP), which props up Liberal Prime Minister Lars Lokke Rasmussen's government in parliament, was calling on voters to reject the proposals, to avoid giving away further sovereignty to Brussels.
The referendum is being seen as a test of whether the Danes will accept or reject greater integration within a 28-member bloc that is being tested more than ever by the migrant crisis, the BBC's Gavin Lee reports from Copenhagen.
Although a Yes vote would not affect Denmark's opt-out on immigration, the DPP argues that it could eventually lead to immigration policies being dictated by the EU. The No campaign's logo is "More EU - No Thanks!"
Thursday's vote comes less than three weeks after jihadist gunmen launched co-ordinated attacks on Paris, murdering 130 people.
Yes campaigners say that cross-border terrorism and the refugee crisis cannot be solved without EU co-operation.
The government believes that without scrapping 22 exemptions on cyber crime, human trafficking and child sexual abuse, Denmark would have to leave Europol because the agency's legal basis changes in 2016.
Unlike Denmark, the UK and Ireland have opt-ins on justice and home affairs legislation, which enable them to choose whether to accept or reject legislation on a case-by-case basis.
Danes voted in 1992 to reject the Maastricht Treaty expanding the EU's powers. The Danish government then negotiated a series of exemptions from EU legislation. In 2000, Denmark also voted not to adopt the euro.
In August, Mr Rasmussen brought the vote forward to December to prevent it becoming caught up in the debate surrounding the UK's referendum which will decide whether it stays in or leaves the EU.
Days after the Danish referendum date was announced, the influx of migrants into northern Europe began, with hundreds crossing from Germany into Denmark.