A loitering munition (LM) is a type of self-destructive unmanned vehicle (aerial (UAV), surface (USV), or underwater, (UUV) ) equipped with a warhead that is typically designed to remotely loiter by a human operator using electro-optical targeting sensors or camera suite and data-link until a target is designated, then crash into it and detonate. Anti-radiation (anti-radar) loitering munitions are a type of loitering munition that employ either an anti-radiation seeker by itself or in tandem with an electro-optical targeting system to locate enemy radar by loitering and destroy it after detection. Common terms like suicide drone, kamikaze drone, or exploding drone are used for both loitering munition and one-way attack drones. They enable attacks against hidden targets that emerge for short periods without placing high-value platforms near the target area. Unlike many other types of munitions, their attacks can be changed mid-mission or aborted. Loitering munitions are typically aerial platforms, but include some autonomous undersea vehicles with similar characteristics.
Loitering weapons emerged in the 1980s for the suppression of enemy air defenses (SEAD) role, and were deployed for SEAD by some military forces in the 1990s. In the 2000s, they were developed for additional roles, from long-range strikes and fire support to short-range tactical systems that fit in a backpack.
History First development and terminology Initially, loitering munitions were not referred to as such but rather as "suicide UAVs" or "loitering missiles". Different sources point at different projects as originating the weapon category. The failed US AGM-136 Tacit Rainbow programAn Introduction to Autonomy in Weapon Systems, pages 13–14, By: Paul Scharre and Michael C. Horowitz, CNAS Working paper, Feb 2015 or the 1980s initial Israeli Delilah variantsLoitering Weapons are making a Comeback, Defense Update, June 2009 are mentioned by some sources.Drone Strike!: UCAVs and Aerial Warfare in the 21st Century, By Bill Yenne, , pages 106–107 The Iranian Ababil-1 was produced in the 1980s but its exact production date is unknown. The Israeli IAI Harpy was produced in the late 1980s.
Early projects did not use the "loitering munition" nomenclature, which emerged much later; they used terminology existing at the time. For instance the AGM-136 Tacit Rainbow was described in a 1988 article:
Initial role in suppression of enemy air defense
In response to the first generation of fixed-installation surface-to-air missiles (SAMs) such as S-75 and S-125, the U.S. military developed SEAD doctrine and Wild Weasel weapons, including anti-radiation missiles (ARMs) such as AGM-45 Shrike. The Soviet Union countered with mobile SAMs such as 2K12 Kub and intermittent use of radar. In Israel's 1982 Operation Mole Cricket 19, UAVs and air-launched Samson decoys were used over suspected SAM areas to saturate enemy SAMs and to bait them to activate their radar systems, which were then attacked by ARMs.Six Days in June (Hebrew), IAF bulletin, issue 145, June 2002Surface to Air Missile Effectiveness in Past Conflicts, Technical Report APA-TR-2010-1001, Dr Carlo Kopp, AFAIAA, SMIEEE, PEng, October 2010
In the 1980s, programs such as the IAI Harpy and AGM-136 Tacit Rainbow integrated anti-radiation sensors into a drone or missile coupled with command and control and loitering capabilities. This allowed the attacking force to put relatively cheap munitions over suspected SAM sites, then attack when the SAM battery was spotted.Meet Israel's 'Suicide Squad' of Self-Sacrificing Drones, August 2016, The DriveADAPTIVE DISCRETE EVENT SIMULATION FOR ANALYSIS OF HARPY SWARM ATTACK, Brandon J. Cobb, Naval Postgraduate School, Thesis, September 2011Loitering, Smart Cruise Missile Marketed to U.S. Navy , National Defense, June 2001
Evolution into other roles
Starting in the 2000s, loitering weapons have been developed for additional roles from relatively long-range strikes and fire supportBritish Army Sets to Deploy Fire Shadow Loitering Weapons to Afghanistan by Early 2012 Defense Update, September 2011 to very-short-range tactical use.Military Investigates Killer Drones That Can Fit in Rucksacks National Defense, July 2011A Tiny Missile That Waits Overhead—Silent, Patient and Deadly, WarIsBoring, January 2014AeroVironment producing Switchblade missiles for Army UPI, October 2016Loitering Autonomous Weapons , Defense Update, January 2007 In the 2016 Nagorno-Karabakh conflict, an IAI Harop was used against a bus used as a troop transport for Armenian soldiers.Israeli-made kamikaze drone spotted in Nagorno-Karabakh conflict, Washington Post, April 2016 The ZALA Lancet loitering munitions and several one-way attack drones including the HESA Shahed 136, have been used by Russia in the Russo-Ukrainian war, while Ukraine has fielded loitering munitions such as the UJ-25 Skyline and the American-made AeroVironment Switchblade, which is deployed to platoons and fits in a backpack.
During conflicts in the 2010s and 2020s, conventional armies and non-state militants began modifying common commercial racing drones into "FPV loitering munitions" by the attachment of a small explosive, so-named because of the first-person view (FPV) they provide the operator. Explosive ordnance such as an IED, grenade, mortar round or an RPG warhead are fitted to an FPV drone then deployed to aerial bomb tactical targets. FPV drones also allow direct reconnaissance during the drone's strike mission.
Since the escalation of the Russo-Ukrainian war in 2022, both Russian and Ukrainian forces were producing thousands of FPV drones every month by October 2023, many of which were donated by volunteer groups. Escadrone Pegasus and the Vyriy Drone Molfar are two examples of the low-cost drones that rapidly evolved in 2022–23 during the war. In 2022, the UK Government announced it was providing "hundreds of loitering munitions" to Ukraine. On 9 November 2023, Ukrainian soldiers claimed to have used a civilian-donated FPV drone to destroy a Russian Tor missile system on the Kupiansk front, showcasing the potential cost-effectiveness of fielding such munitions. A Tor missile system costs some $24 million to build, which could buy 14,000 FPV drones.
Some multirole loitering munitions, such as the Eren, made by the Turkish company Roketsan, can play the role of an interceptor drone by destroying enemy aerial platforms including UAVs while retaining their ground attack capabilities. On 23 February 2026, a Baykar Bayraktar Akinci UCAV successfully destroyed a target drone with the Eren loitering munition.
The Israeli Spike Firefly, developed by Rafael Advanced Defense Systems, has been used in the Gaza Strip for its precision and ability to strike targets behind cover. Usage was confirmed by the manufacturer in 2024.
Characteristics
Loitering munitions may be as simple as an unmanned aerial vehicle (UAV) with attached explosives that is sent on a potential kamikaze mission, and may even be constructed with commercially available quadcopters with strapped-on explosives.ISIS Using Kamikaze Drones in Iraq, Popular Mechanics, October 2016 Purpose-built quadcopter loitering munitions were also made such as the STM Kargu.
Purpose-built munitions are more elaborate in flight and control capabilities, warhead size and design, and onboard sensors for locating targets.iClean – Loitering Attack UCAV, Artzi Dror, Technion Institute of Technology, 2012 Most of the loitering munitions use a human operator to remotely locate targets such as IAI Harop. On the other hand, anti-radar loitering munitions such as IAI Harpy can function autonomously searching and launching attacks against radar without human intervention using an anti-radiation seeker.Israel Unveils Loitering Anti-Missile Drone , Defense Update, 2009Harpy Air Defense Suppression System , Defense Update, 2006 Its latest compact variant Mini Harpy is equipped with both the electro-optical targeting system and anti-radiation seeker.
Some loitering munitions have double X-shaped wing configuration such as ZALA Lancet and UVision HERO series. Loitering systems are operated remotely, controlled in real time by a communications system and equipped with an electro-optical camera whose images are received by the command and control station.
Some loitering munitions may return and be recovered by the operator if they are unused in an attack and have enough fuel; in particular this is characteristic of UAVs with a secondary explosive capability.IAI's ROTEM – Tactical Multirotor Killer Drone, Defense Update, 2016 Other systemsThe Secrets of Delilah (Hebrew), IAF bulletin, issue 184, December 2008 do not have a recovery option and are self-destructed in mission aborts. Some jet-powered loitering munitions such as Roketsan's Eren and Delilah structures are more similar to missiles than unmanned aerial vehicles.Delilah – The IAF Loitering Missile, Defense Update, June 2009
Countermeasures Russia has continually utilized ZALA Lancet drones in Ukraine. Since spring 2022 Ukrainian forces have been building cages around their artillery pieces using chain link fencing, wire mesh and even wooden logs as part of the construction. One analyst told Radio Liberty that such cages were "mainly intended to disrupt Russian Lancet munitions." A picture supposedly taken from January 2023 shows the rear half of a Lancet drone that failed to detonate due to such cages. Likewise Ukrainian forces have used inflatable decoys and wooden vehicles, such as HIMARS, to confuse and deceive Lancet drones.
Ukrainian soldiers report shooting down Russian drones with sniper rifles. Russian soldiers use electronic warfare to disable or misdirect Ukrainian drones and have reportedly used the Stupor anti-drone rifle, which uses an electromagnetic pulse that disrupts a drone's GPS navigation. A Royal United Services Institute study in 2022 found that Russian Electronic Warfare units, in March and April 2022, knocked out or shot down 90% of Ukrainian drones that they had at the start of the war in February 2022. The main success was in jamming GPS and radio links to the drones.
Both Ukraine and Russia rely on electronic warfare to defeat FPV drones. Such jammers are now used on Ukrainian trenches and vehicles. Russian forces have built jammers that can fit into a backpack. Pocket-size jammers for soldiers were also developed. As of June 2023 Ukraine was losing 5–10,000 drones a month, or 160 per day, according to Ukrainian soldiers.
This has led to Russia creating wire guided FPV drones, similar to a wire-guided missile or even wire-guided torpedoes. Those drones typically have fibre optic cables 5–20 km in length. Such guidance makes the link between operators and FPV drone immune to jamming. It also allows for much faster and better quality updates from the drone, even from locations where radio contact would be poor, and doesn't reveal operator's or drone's location by radio signals. They also need less power to communicate, and so can be used to idle on the ground for ambushes. They have reduced range, payload and manoeuvrability compared to wireless drones, although in practice, range and agility of the wired drones can be even higher than those of the radio-controlled ones, given their reduced control latency and increased survivability. Ukraine has also responded by using autonomous drones tasking to ensure that a jammed drone can hit a target. In March 2024 footage put on social media showed a Ukrainian FPV drone being jammed just before it struck a target. Despite the loss of operator control it still managed to strike the target.
Russian tanks have been fitted with rooftop slat armor at the beginning of the Russian invasion of Ukraine which could provide protection against loitering munitions in some circumstances. Some Ukrainian tanks taking part in the 2023 Ukrainian counteroffensive were also spotted using roof screens.