Voters in Scotland went to the polls Thursday to decide whether to end their country’s 307-year-old union with Britain and become an independent state.

Voters in Scotland went to the polls Thursday to decide whether to end their country's 307-year-old union with Britain and become an independent state.

Polls opened across the nation at 7 a.m. local time (2 a.m. Eastern) and will close at 10 p.m. (5 p.m. Eastern).

The first results are not expected to be announced until early Friday Turnout is expected to be high, with 4.2 million people registered to vote -- 97 percent of eligible voters.

Opinion polls suggest that the race is too close to call, though most surveys taken in the final days of the campaign have given the pro-Union "No" side a slight lead, Fox News reported.

In Scotland's capital, Edinburgh, a heavy stream of voters began arriving at a polling station in the city center the moment it opened.

British Prime Minister David Cameron has pleaded with Scottish voters not to secede, and predictions of economic doom, military upheaval and isolation have dogged the debate.