WASHINGTON (AP) — As the U.S. prepares to see more drones aloft in coming years, President Barack Obama is taking steps to ensure that the government respects privacy and civil liberties when it uses the unmanned aircraft to collect information.

Obama issued a memorandum to federal agencies Sunday specifying measures to guard against abuse of data collected in drone flights.

Among other steps, the order requires agencies to review privacy and civil rights protections before deploying drone technology and to follow a range of controls.

Personally identifiable information collected in drone flights is to be kept no longer than 180 days, although there are exceptions.

It's questionable whether such steps will satisfy civil liberties advocates, who've objected strongly to the government's vigorous use of digital surveillance in the name of national security.