Queen Elizabeth II has made her first comments about this week's Scottish independence vote, urging Scots to "think very carefully about the future."

But the popular British monarch didn't indicate a preference on how Scots should vote, carefully maintaining the neutrality that is her constitutional obligation.

Still, some may interpret her comments as a suggestion that Scots looking to embrace independence should be cautious about severing Scotland's long ties to the United Kingdom, which date back more than 300 years.

The queen spoke after a Sunday church service near her Balmoral estate in Scotland. She made the comment to a well-wisher in the crowd.

Buckingham Palace recently issued a statement indicating her plans to remain neutral before Thursday's vote.

She was seen as resisting calls from some Conservative Party lawmakers that she should make her views known before the historic vote because it could possibly lead to a breakup of the United Kingdom.

She is well known to have a deep affection for Scotland and to spend much of her free time every summer at her extensive Balmoral estate, where she can be seen walking in the woods or riding horses.

Weekend polls have suggested the race is too close to call with both sides planning a frenetic final few days of campaigning.

Prime Minister David Cameron is expected to return to Scotland to attempt to persuade voters to reject independence and remain part of the United Kingdom.

The "Better Together" campaign has been emphasizing the economic uncertainties that would face an independent Scotland, while pro-independence forces have been predicting a rosy future for an oil-rich Scotland free of the United Kingdom.

If Scotland votes for independence, it would split from the United Kingdom in 18 months. Scottish leaders have indicated a desire to have the queen serve as head of state of an independent Scotland if the Yes campaign triumphs.