A request for drones from a California sheriff's office prompted the American Civil Liberties Union to point out, what officials say, are significant dangers posed by the proliferation and misuse of the aerial surveillance devices.

The Alameda County Sheriff's office in Northern California has requested a grant to purchase unmanned aerial drones for video and infrared surveillance in police, fire and rescue settings, according to Pleasanton Patch.

Sheriff Gregory Ahern insists a drone deployed by his department would not be used as a "patrol tool."

"It would be a mission-specific tool for evaluating and testing for specific incidents," Ahern said. "If we do this, we have to have permission from the [federal aviation administration] defined for each specific type of mission such as search and rescue, fires or for explosive ordinances teams to take photos of suspicious devices."

But the civil liberties group notes that strong "safeguards and accountability mechanisms" must be in place to ensure that "law enforcement does not use drones to engage in warrantless mass surveillance," according to an ACLU blogpost.

Ahern touted the affordability of drones, noting that a single drone costs between $50,000 to $100,000, whereas a helicopter costs $3 million and is expensive to operate.

But the ACLU sees the cheapness of drones as another potential danger.

"When the police have to mount elaborate and costly foot and squad patrols to follow a suspect 24/7, the expenditure of resources serves as a deterrent to abuse; it forces the police to limit their surveillance to instances when it is actually necessary," the blog post says. "Drones permit the police to surveil people at all hours of the day and, apparently, at 1/30 the cost of other forms of aerial surveillance. The natural deterrent to abuse goes away, and invites abuse."

Current Guardian columnist and former Salon blogger Glenn Greenwald echoed those concerns in a December, 2011 piece.

The fact is that drones vest vast new powers that police helicopters and existing weapons do not vest: and that’s true not just for weaponization but for surveillance. Drones enable a Surveillance State unlike anything we’ve seen. Because small drones are so much cheaper than police helicopters, many more of them can be deployed at once, ensuring far greater surveillance over a much larger area. Their small size and stealth capability means they can hover without any detection, and they can remain in the air for far longer than police helicopters.

Armed drones have become a common and controversial tool used in the so called "War on Terror" overseas.

Congress approved the use of unarmed drones in the US earlier this year.

Since then, worry over privacy and other civil rights abuses has inspired legislation in Congress that would put some clamps on law enforcement's ability to use the unmanned aircrafts.

“When it comes to privacy protections for the American people, drones are flying blind,” Rep. Ed Markey (D-Mass.) said in a statement released in August. “Drones are already flying in U.S. airspace – with thousands more to come – but with no privacy protections or transparency measures in place."

Also on HuffPost:

Loading Slideshow...
  • Kelly Thomas

    FILE - This July 5, 2011 file still frame from security camera video, released May 7, 2012, by the Orange County District Attorney, shows an altercation between Fullerton police officers and Kelly Thomas at the Fullerton, Calif., bus depot. Thomas died days later. Two officers, Manuel Ramos, and Jay Ciccinelli, are on trial charges related to his death. Closing arguments are scheduled to begin Tuesday, Jan. 7, 2013. (AP Photo/Orange County District Attorney, File)

  • Oscar Grant BART shooting

    Oscar Grant was shot by a Bay Area Rapid Transit (BART) police officer early on New Year's Day 2009 in Oakland, Calif. Cellphone footage shows BART cops struggling with Grant and forcing him to lay facedown on the platform after reports of a fight on the train. Officer Johannes Mehserle was seen shooting Grant in the back once, killing him. He was later convicted of involuntary manslaughter, but acquitted of second degree murder.

  • Rodney King Beating

    In one of the most notorious cases of police brutality, a bystander recorded four Los Angeles Police Department officers beating Rodney King with their batons in 1991 after they pulled him over for driving erratically. When the videotape emerged days later of the attack, the four cops were charged with assault. A jury acquitted them, sparking riots in April 1992 that killed 55 people and led to 12,000 arrests over seven days.

  • Anthony Abbate

    Off-duty Chicago police officer Anthony Abbate was<a href="http://www.huffingtonpost.com/2009/06/23/ex-cop-anthony-abbate-get_n_219651.html" target="_hplink"> sentenced to two years probation</a> and anger management classes after being captured on video beating a female bartender in 2007.

  • William Cozzi

    Chicago police officer William Cozzi was sentenced to 40 months in federal prison after he was caught on camera in 2005 handcuffing a man to a wheelchair and beating him in a hospital. Cozzi claimed the victim -- a man who was seeking treatment for stab wounds -- had attacked him.

  • Christopher Long

    A New York City police officer was <a href="http://www.huffingtonpost.com/2010/07/15/patrick-pogan-biker-shove_n_646517.html " target="_hplink">acquitted of assault and harassment</a> after being videotaped <a href="http://www.huffingtonpost.com/2008/07/28/critical-mass-bicyclist-a_n_115390.html " target="_hplink">knocking over cyclist Christopher Long</a> during a "Critical Mass" bike ride through Times Square in 2008. Patrick Pogan resigned from the police force and was found guilty of filing false documents after video emerged that contradicted his claim that Long swerved into him.

  • Ahmed Amadou Diallo

    Ahmed Amadou Diallo, 22, seen here in an undated photo, was gunned down at his home in the Bronx borough of New York early Thursday morning, Feb. 4, 1999. Four white police officers from the elite Street Crime Unit fired 41 shots at Diallo, a black West African immigrant who had no police record and was unarmed. Diallo was hit 19 times and died instantly. The officers' lawyer says Diallo gestured with his hands, leading the police to think he was reaching for a gun.

  • Abner Loiuma

    Abner Loiuma became a symbol of unchecked police force after the Haitian immigrant was sodomized with a broomstick by cops in a New York City police station in 1997. The officer responsible for the attack, Justin Volpe, was sentenced to 30 years in prison.

  • Ian Tomlinson

    London newspaper vendor Ian Tomlinson died after police officer Simon Harwood hit him with a baton and <a href="http://www.huffingtonpost.com/2009/04/09/british-police-officer-su_n_185251.html " target="_hplink">knocked him to the ground</a> as he walked away from police during a G-20 protest in 2009. Harwood will stand trial in October for manslaughter, <a href="http://www.guardian.co.uk/uk/2011/jun/20/ian-tomlinson-death-officer-trial" target="_hplink">according to The Guardian</a>.

  • Michael Mineo

    Michael Mineo accused an NYPD cop of sodomizing him with a baton after getting busted for smoking marijuana at a Brooklyn subway station in October 2008. A jury cleared the officer accused in the attack as well as two others charged with covering up the alleged assault.

  • Jon Burge

    In this May 24, 2010 file photo, former Chicago Police commander Jon Burge departs the federal building in Chicago. Burge, whose name has become synonymous with police brutality and abuse of power in Chicago, was convicted in 2010 of perjury and obstruction of justice for lying in a civil suit when he said he'd never witnessed or participated in the torture of suspects.

  • Danziger Bridge Shootings

    The trial is underway for four New Orleans police officers accused of killing two people and wounding four others in the shooting on the Danziger Bridge in the aftermath of Hurricane Katrina in 2005. The suspects, pictured left to right, are Robert Faulcon Jr., Robert Gisevius Jr., Kenneth Bowen, and Anthony Villavaso II.

  • David London

    Security cameras in a Manhattan apartment building recorded NYPD officer David London hitting Iraq war veteran Walter Harvin almost 20 times with a baton even after he had handcuffed him. The incident began when Harvin entered the building without a key and refused to identify himself to London. Footage shows Harvin shoved London, but the cop lied to investigators by claiming that he'd been punched before retaliating with his baton. A jury acquitted London of assault and making false statements in 2010.

  • Eleanor Bumpurs

    Eleanor Bumpurs, a 66-year-old African American woman, was killed by NYPD officers who were trying to evict her from her Bronx public housing apartment in 1984 for falling behind on her rent. City housing authority workers called in the cops, because they claimed that Bumpurs -- shown in an undated photo -- was mentally ill and that she menaced them with a knife while refusing to vacate her home. The officer who shot Bumpers twice with a shotgun was acquitted in 1987.

  • Sean Bell

    The 2006 shooting of 23-year-old Sean Bell raised questions in New York City about the NYPD's use of excessive force. On what would have been his wedding day, Bell was shot and killed by police in a hail of 50 bullets outside a strip club in Queens. Officers said they thought the victim and his friends, who were celebrating Bell's bachelor party, were planning on retrieving a gun from their vehicle when they opened fire. After months of protests around the city, Officers Michael Oliver, Gescard Isnora and Marc Cooper were acquitted in 2008.