The Federal Aviation Administration is expected to announce Thursday that it is granting permits to seven movie and television production companies to fly drones, an important step toward greater use of the technology by commercial operators, said attorneys and a company official familiar with the decision.

However, the permits are expected to come with limitations, including that the unmanned aircraft be used only on closed sets and that they be operated by a three-person team, including a trained drone operator.

Until now, the only permit for commercial drone operations the FAA has granted has been to the Conoco Phillips oil company, which has flown two kinds of unmanned aircraft in unpopulated areas of Alaska and over the Arctic Ocean with significant limitations on their use.

The FAA is under intense pressure from Congress and a plethora of industries that want to use the technology or sell it to others to relax its ban on commercial drone use. Companies want to use drones to monitor pipelines, inspect the undersides of oil platforms and bridges, and spray crops. Amazon and Google want to use them to deliver packages. Wedding videographers, real estate agents, journalists and other many others are clamoring to use them as well.

The seven movie and television companies are regarded by agencies as trailblazers, the first of what are likely to be dozens of industries that could be approved in coming months for drone operations under limited circumstances.

"The floodgates will open and we'll see all kinds of other entities looking to use these things," said Lisa Ellman, an attorney with McKenna, Long & Aldridge who formerly headed the Justice Department's working group on drone policy

But Brendan Schulman, a New York attorney who presents several drone operators and interest groups that have challenged the FAA's drone restrictions, said he is concerned that limitations attached to the drone permits may be so onerous that the benefits of using the drones will be outweighed by the cost and the headache of complying with regulations.

"I'm worried that it's too small a step forward and it's too narrowly limited," he said.

The seven companies—Aerial MOB LLC, Astraeus Aerial, Flying-Cam Inc., HeliVideo Productions LLC, Pictorvision Inc., Vortex Aerial and Snaproll Media LLC—have been working with the Motion Picture Association of America for two years to win FAA approval.

Tony Carmean, a partner in Aerial MOB of San Diego, predicted drones will fundamentally change moviemaking, providing directors with the ability to get shots they could never get before and making films more dynamic. Small drones with video cameras will be able to fly through a building and in and out of windows, for example, he said.

Major movie studios "want their hands on this right away," but have held off using the technology until the FAA gives the go-ahead, he said.

© 2014 The Associated Press. All rights reserved.