The United States government has carried out some targeted airstrikes against alleged terrorists in Yemen and violated international law, says a new report released by Human Rights Watch Tuesday.

The organization's 97-page report examines six incidents, most using armed drones, from 2009-13. At least 57 civilians died because of the strikes, which killed 82 people.

"The U.S. says it is taking all possible precautions during targeted killings, but it has unlawfully killed civilians and struck questionable military targets in Yemen," said Letta Tayler, who works for the organization and wrote the Between a Drone and Al-Qaeda: The Civilian Cost of U.S. Targeted Killings in Yemen report.

Human Rights Watch researchers spent six weeks in the country interviewing nearly 100 people, including witnesses and relatives, about the strikes.

"Yemenis told us that these strikes make them fear the US as much as they fear Al-Qaeda in the Arabian Peninsula," said Tayler.

All six attacks either killed civilians indiscriminately, targeted illegitimate military objectives or caused disproportionate civilian deaths, according to the report.

"The bodies were charred like coal - I could not recognize the faces," said Ahmad al-Sabooli, a 23-year old farmer whose mother, father and 10-year-old sister died in one of the attacks.

During these operations, the U.S. government may be using "an overly elastic definition of a fighter who may be lawfully attacked during an armed conflict," said Human Rights Watch in a press release.

The American government and Yemeni authorities both declined to comment on the investigation.

Amnesty International released a separate report Tuesday on U.S. drone strikes in Pakistan.

Both organizations are calling for Congress to investigate the cases outlined in the two reports and any other potentially unlawful strikes.

"The US should investigate attacks that kill civilians and hold those responsible for violations to account," Tayler said. "It’s long past time for the US to assess the legality of its targeted killings, as well as the broader impact of these strikes on civilians."

Human Rights Watch admits the applicability of international humanitarian law is sometimes unclear, adding America's battle with Al-Qaeda does "not appear to meet the intensity required under the laws of war to amount to an armed conflict."

However, America should still follow international human rights law, said the organization, which only permits using deadly force "when strictly and directly necessary to save human life."

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  • Boeing Phantom Ray

    <strong>Type</strong>: Military (U.S.) <strong>Description</strong>: Boeing's stealth Phantom Ray took to the skies for the <a href="http://www.boeing.com/Features/2011/05/bds_phantom_ray_first_flight_05_04_11.html" target="_hplink">first time in April 2011</a>. According to Boeing, the <a href="http://www.boeing.com/advertising/bma/unmanned/unmanned_05.html" target="_hplink">Phantom Ray can perform missions</a> such as intelligence, surveillance and reconnaissance; suppression of enemy air defenses; and electronic attack. <strong>Potential Deployment</strong>: Unknown. This is a "demonstrator" so there will likely be a future variation of the Ray.

  • General Atomics Predator Avenger

    <strong>Type</strong>: Military (U.S.) <strong>Description</strong>: General Atomics Aeronautical Systems <a href="http://www.ga-asi.com/products/aircraft/predator_c.php" target="_hplink">Predator Avenger C</a> is a beast. According to the two-page brochure, the PAC is a "Next-Generation Multi-mission ISR and Strike Aircraft" and successor for the Predator B that can be stacked with a multitude of weaponry. <strong>Deployment</strong>: There is one <a href="http://www.aviationweek.com/aw/generic/story.jsp?topicName=unmanned&id=news/awst/2011/12/19/AW_12_19_2011_p25-406500.xml&headline=USAF Plans Larger, More Capable Predator&channel=&from=topicalreports" target="_hplink">demonstration craft currently in Afghanistan</a>.

  • SOCOM Mini Drone Of Doom

    <strong>Type</strong>: Military (U.S.) <strong>Description</strong>: Yo dawg, I heard you like drones so I <a href="http://www.wired.com/dangerroom/2011/10/socom-warhead-drones/" target="_hplink">put a drone in your drone</a>. One small deadly warhead-equipped mini-drone stuffed into another, to be launched from the main drone and remotely aimed at a target. <strong> Potential Deployment</strong>: This <a href="http://defensenewsstand.com/NewsStand-General/The-INSIDER-Free-Article/socom-could-have-warhead-equipped-micro-uav-by-spring-2012/menu-id-720.html" target="_hplink">warhead-equiped micro-UAV</a> could be flown by SOCOM in the skies by spring 2012.

  • Suicide Switchblade

    <strong>Type</strong>: Military (USA) <strong>Description</strong>: <a href="http://www.avinc.com/uas/adc/switchblade/" target="_hplink">AeroVironment's Switchblade</a> is meant to be a portable, rapid deployment, beyond line-of-sight, "loitering munition" that is a "magic bullet." A bit of advice, AeroVironment: Don't describe a remote-controlled bomb as a "loitering munition" that you call "Switchblade," as it conjures up images of 1950's-style greasers loitering on street corners, flipping open switchblades idly as they wait for their favorite gals. Luckily, greasers won't be in charge of flying Switchblades. They're to be controlled by infantry and <a href="http://www.defensenews.com/story.php?i=7982421&&s=TOP" target="_hplink">according to the AeroVironment</a>, "Flying quietly at high speed the Switchblade delivers its onboard explosive payload with precision while minimizing collateral damage." <strong>Potential Deployment</strong>: Undisclosed.

  • Nano Hummingbird

    <strong>Type</strong>: Surveillance (USA, DARPA Funded) <strong>Description</strong>: AeroVironment is at it again. In partnership with DARPA, they've actually managed to build a human mechanically engineered version of one of nature's most amazing flying machines: the hummingbird. The <a href="http://www.avinc.com/media_gallery/" target="_hplink">Nano Hummingbird</a> is a perfect bid for James Bond-esque style spy shenanigans. Once these hit the field, we'll never look at hummingbirds the same way. "Stop looking at me! That bird is following me!" <strong>Potential Deployment</strong>: Within five years.

  • Army A160 Hummingbird Drone

    <strong>Type</strong>: Military (U.S. Army) <strong>Description</strong>: Though the military's <a href="http://www.huffingtonpost.com/2011/12/30/us-army-hummingbird-a160-helicopter-drone_n_1176763.html?ref=technology" target="_hplink">A160 Hummingbird drone</a> doesn't resemble an actual hummingbird so much as AeroVironment's take, it is <a href="http://www.salon.com/2011/12/06/nprs_domestic_drone_commercial/" target="_hplink">raising just as many alarms</a> because of its potential to be deployed on the U.S. home front. <strong>Potential Deployment</strong>: May or June 2012, Afghanistan

  • Firescout

    <strong>Type</strong>: Military (U.S. Navy) <strong>Description</strong>: Northrop Grumman <a href="http://www.as.northropgrumman.com/products/mq8bfirescout_navy/index.html" target="_hplink">describes the Firescout</a> as a "Transformational Fire Scout Vertical Takeoff and Landing Tactical Unmanned Aerial Vehicle system provides unprecedented situation awareness and precision targeting support for U.S. Armed Forces of the future. The MQ-8B Fire Scout has the ability to autonomously take off and land on any aviation-capable warship and at prepared and unprepared landing zones in proximity to the soldier in contact." <strong>Potential Deployment</strong>: <a href="http://www.irconnect.com/noc/press/pages/news_releases.html?d=237497" target="_hplink">March 2013</a>

  • Euro Hawk

    <strong>Type</strong>: Military (German Ministry of Defense, purchased from Northrop Grumman) <strong>Description</strong>: NG touts its <a href="http://www.as.northropgrumman.com/products/euro_hawk/index.html" target="_hplink">Euro Hawk</a>, built for German Ministry of Defense, as having a "wingspan larger than a commercial airliner, endurance of more than 30 hours and a maximum altitude of more than 60,000 feet, EURO HAWK is an interoperable, modular and cost-effective replacement to the aging fleet of manned Breguet Atlantic aircraft, which have been in service since 1972 and will be retired in 2010." <strong>Potential Deployment</strong>: 2015, 2016 (<a href="http://www.as.northropgrumman.com/products/euro_hawk/assets/SIGINT_NewsRelease_101211.pdf" target="_hplink">PDF</a>)

  • X-47B

    <strong>Type</strong>: Military (U.S. Navy) <strong>Description</strong>: A carrier-based combat drone, <a href="http://www.as.northropgrumman.com/products/nucasx47b/index.html" target="_hplink">Northrop Grumman's futuristic X-47B</a> flew in its cruise configuration <a href="http://www.irconnect.com/noc/press/pages/news_releases.html?d=239278" target="_hplink">for the first time</a> on November 22, 2011. It can land with precision on the deck of a moving aircraft carrier, and features twin weapons payload bays that hold up to 4,500 lbs. (<a href="http://www.as.northropgrumman.com/products/nucasx47b/assets/X-47B_Navy_UCAS_FactSheet.pdf" target="_hplink">PDF</a>). <strong>Potential Deployment</strong>: <a href="http://www.wired.com/dangerroom/2011/11/navy-killer-drone-refuel/" target="_hplink">2018</a>

  • Taranis

    <strong>Type</strong>: Military (British) <strong>Description</strong>: BAE System's Taranis (<a href="http://www.baesystems.com/BAEProd/groups/public/documents/bae_publication/bae_pdf_taranis_fact_sheet.pdf" target="_hplink">PDF</a>) is aiming to "Push the boundaries by providing advancements in low observability capability and autonomous mission systems operations demonstrating the feasibility and utility of UAVs." Such a statement starts to push the idea of fully autonomous flight from science fiction into science fact, though we're still a long way off from having an actual real debate on fully autonomous drones fighting our battles and flying our skies. Potential Deployment: TBD, test flights have been delayed to 2012.

  • Boeing Phantom Eye

    <strong>Type</strong>: Communications <strong>Description</strong>: Boeing's hydrogen-powered <a href="http://www.boeing.com/Features/2010/07/bds_feat_phantom_eye_07_12_10.html" target="_hplink">Phantom Eye</a> is a High Altitude Long Duration Craft designed to fly at <a href="http://www.boeing.com/Features/2011/11/bds_phantom_eye_11_16_11.html" target="_hplink">65,000 feet for up to four days</a>. <strong>Potential Deployment</strong>: Unknown

  • DARPA Vulture

    <strong>Type</strong>: Intelligence, Surveillance, and Reconnaissance (ISR) <strong>Description</strong>: <a href="http://www.darpa.mil/Our_Work/TTO/Programs/Vulture.aspx" target="_hplink">DARPA's description</a> says the "Vulture technology enables a re-taskable, persistent pseudo-satellite capability, in an aircraft package." Basically, DARPA is attempting to develop a super long duration craft capable of five year continuous flight. Think about that - the Vulture is intended to fly for up to five years continuously. If it were to launch this year it would be in the air for two Olympics. <strong>Potential Deployment</strong>: Unknown

  • AVIATR: Drone To Fly Saturn's Moon

    <strong>Type</strong>: Government Funded Space Exploration <strong>Description</strong>: While the proposal probably won't go through for this mission, this is an aerial drone we can really get behind. <a href="http://www.huffingtonpost.com/2012/01/04/aviatr-probe-proposed-mission-titan_n_1184028.html" target="_hplink">AVIATR</a> would be a long distance drone that would fly the skies of Saturn's moon Titan. <strong>Potential Deployment</strong>: Beyond 2020

  • Japan Defense Ministry Ball Drone

    <strong>Type</strong>: Surveillance (Japan) <strong>Description</strong>: Techcrunch <a href="http://techcrunch.com/2011/10/25/video-japans-defense-ministry-develops-awesome-ball-shaped-drone/" target="_hplink">tells us</a> that the drone can "stand still in mid-air, fly vertically and horizontally through narrow spaces at up to 60km/h, and (which is very cool) keep on moving when it hits the ground or a wall. Thanks to three gyro sensors in its body, the machine can keep also flying even if it's hit by an obstacle." And all for only $1,400. <strong>Potential Deployment</strong>: Undisclosed