Danes vote in parliament elections with left, right being neck-and-neck

The Social Democrats, headed by Prime Minieter Helle Thorning-Schmidt, held it's closing press conference of their election campaign in the Danish Parliament Christiansborg Castle Wednesday June 17. 2015, in Copenhagen. Denmark will hold a mandatory general election Thursday June 18 after almost four-years of coalition Government between the Social Democrats and the Social-Liberal Party. (Jens Dresling/Polfoto via AP) DENMARK OUT (The Associated Press)

Danish Prime Minister and head of the Social Democrats, Helle Thorning-Schmidt, leaves the voting booth after casting her vote Thursday June 18, 2015 at the polling station in Copenhagen. Denmark is holding a general election Thursday where approximately 4 million voters are entitled to cast their ballots to elect the 179 members of the parliament. (Lars Krabbe/Polfoto via AP) DENMARK OUT (The Associated Press)

Danish Prime Minister and head of the Social Democrats, Helle Thorning-Schmidt, and her husband British politician Stephen Kinnock, arrive Thursday June 18, 2015 at the polling station in Copenhagen. Denmark is holding a general election Thursday where approximately 4 million voters are entitled to cast their ballots to elect the 179 members of the parliament. (Lars Krabbe/Polfoto via AP) DENMARK OUT (The Associated Press)

Danes are voting in parliamentary elections that will determine whether the center-left government of Prime Minister Helle Thorning-Schmidt can continue or whether the center-right opposition will be back at the helm.

Both Thorning-Schmidt's Social Democrats and opposition leader Lars Loekke Rasmussen's Liberals depend on other parties to build a majority in the 179-seat Folketing, or Parliament.

Ahead of Thursday's vote, polls show them neck-and-neck with their campaigns focusing on the impact of immigration on the welfare system, among other issues. Both sides have promised to further tighten Denmark's controls on immigration.

Loekke Rasmussen, a former prime minister, needs support from the populist Danish People's Party that wants border controls back to stop foreign criminals from entering the country.