Twenty-seven states, including Virginia, are trying to determine whether the use of domestic drones by law enforcement agencies would be a boon to crime-fighting or a serious threat to the privacy of average Americans.

The Virginia General Assembly last month passed a bill with strong bipartisan support that bans police in the state from using unmanned aircraft systems for the next two years while the state works on guidelines for using the technology. Gov. Bob McDonnell has not said whether he will sign the measure into law.

No other state is so close to passing a similar sweeping moratorium, according to a breakdown of drone legislation provided by the National Conference of State Legislatures. The Maryland legislature will hold a hearing later this month on a bill that would prohibit drone use by police without a warrant.

Drones have become a new hot issue in state capitals across the country because a growing number of local police departments want to start using them to help with surveillance. But as the public has grown more aware of the technology, it has also grown wary of it.

"States are looking to balance the practical applications of this emerging technology for law enforcement and the general public with privacy concerns," said Rich Williams, a criminal justice expert with NCSL. "Bills have been introduced on this issue the past few years, but there has been substantially more activity this year."

The Virginia bill, sponsored by Del. Ben Cline, R-Amherst, was amended to allow drones to be used in the National Guard training exercises, to help find lost children or senior citizens and to assist in search-and-rescue missions -- changes sought by McDonnell.

It's unclear whether the changes make the bill easier for McDonnell to sign, but the Republican has already suggest he supports the use of drones by first responders and during terrorist hunts.

"When most folks come to understand the power of this new technology -- the fact an item six inches long can be seen from 6,000 feet, they can see through roofs with infrared technology and don't require a warrant -- it concerns people," Cline said.

- Steve Contorno