The Israel Defense Forces (IDF) reported February 23 that it had downed an unmanned aerial vehicle (UAV) over the Mediterranean after it was launched from the Gaza Strip. According to IDF sources, an Israeli F-16 shot down the UAV, which it said belonged to Hamas, before it was able to cross into the country’s airspace. Details of the type of drone and its mission remain sparse, but the flight demonstrates Hamas’s determined pursuit for UAV capability even after the death of its chief drone engineer last month in Tunisia. While Hamas’s nascent drone program has yet to produce any tactical or strategic advantage, the use of drones by terrorist organizations elsewhere in the region underscores the challenges they can pose.

Hamas reportedly tested its first drone in 2012, after which the IDF quickly targeted the site believed to house the program. A year later, Palestinian security forces foiled Hamas operatives in the West Bank plotting to launch UAVs packed with explosives that would strike targets in Israel. It was not until summer 2014, however, that Hamas launched a UAV that breached Israeli airspace, reaching the seaside city of Ashdod before being quickly downed by a Patriot surface-to-air missile. Hamas attempted to fly a UAV into Israeli airspace in June 2015, but it crashed just after crossing the border fence. Last September, another UAV appeared above the Gaza coast before also being quickly downed by an Israeli fighter.

Although Hamas’s drones appear largely unsuccessful in giving the group any tactical advantage thus far, its allies in Lebanon have had more success breaching Israel’s airspace with Iranian-produced UAVs, even conducting long-range flights that avoided detection until they approached sensitive areas. In October 2013, an Ababil UAV operated by Hezbollah managed to fly from south Lebanon over the Mediterranean and Gaza and into Israel, where it approached the Dimona nuclear reactor – a more than 145-mile flight – before it was downed by an Israeli fighter. While it is unknown if the UAV gleaned any sensitive information, the fact that it avoided interception and flew 35 miles into Israel proved a propaganda win for Iran and Hezbollah.

This breach and others have demonstrated the challenge for Israel of detecting and downing small, low-flying drones as they creep across the border. When an unidentified UAV flew over the Golan Heights in July 2016, it managed to dodge two Patriot missiles and an air-to-air missile fired from an Israeli fighter before it returned to Syrian airspace unscathed. The incident was later revealed to be an accidental Russian incursion.

While the drone threat does not affect the military balance between Israel and Hamas, it can allow the group to conduct more accurate attacks. As one IDF general notes, when armed, the UAVs can act as a “poor man’s cruise missile,” giving terror groups long-range precision strike capability.

The ongoing battle of Mosul further demonstrates how resourceful a terrorist group can be in developing improvised armed drones. Media reports and propaganda videos indicate that ISIS has used UAVs to conduct strikes on Iraqi and Kurdish forces. One incident in October killed two Kurdish fighters and wounding two French advisors operating behind the front line. The group also frequently uses drones to film its vehicle-borne IED attacks on adversaries, hoping to convey the message that it remains a potent fighting force.

Israel and the U.S. have devoted significant resources to defending against aircraft and ballistic missiles. However, these defenses are not always reliable against smaller and slower-moving targets. Fortunately, the probing of Israeli air defenses by terror groups’ drones has served as a warning to improve countermeasures before such a threat becomes lethal.

The U.S. and Israel have already upgraded and tested the Iron Dome system against UAVs, while Israeli defense firms Elbit and Rafael have both developed new counter-UAV systems. The U.S. Air Force also recently awarded a $15.6-million contract to Israeli Aerospace Industries for a detection and jamming system to counter ISIS UAVs. Last month’s downing of a Hamas drone suggests the IDF is already making progress in mitigating the threat posed by terror groups deploying drones.

Patrick Megahan is a research analyst at the Foundation for Defense of Democracies focusing on military affairs. He manages the website John Cappello is a senior fellow at the Foundation for Defense of Democracies focusing on military affairs and a former U.S. Air Force B-1 Lancer pilot.