On Saturday, President Nicolas Maduro of Venezuela was giving a speech in Caracas when two armed drones exploded nearby -- one detonating in the air and another inside an apartment building, authorities said.
President Maduro blamed far-right political opponents for what he called an attempted assassination. Six people have been arrested.
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The apparent attack raises the question: Could a drone assassination work? This would certainly change the way governments handle security for heads of state in public events. It also has implications for the security of overseas military bases and embassies.
The global proliferation of drones
The United States was the first to use armed drones after the 9/11 attacks. Since then, Azerbaijan, Iran, Iraq, Israel, Nigeria, Pakistan, Turkey, the United Arab Emirates and the United Kingdom have all used armed drones in combat.
It was President Barack Obama who dramatically increased the use of armed drones against suspected terrorists in countries that the United States is not at war with, such as Libya, Pakistan, Somalia and Yemen.
A number of countries have used drones to assassinate their own citizens. Both the United States and the United Kingdom have conducted strikes against their own citizens overseas, while Israel has done so in the Palestinian territories. Countries such as Nigeria, Turkey, Pakistan, and Iraq have conducted drone strikes within their own borders.
Another 19 countries have armed drones but have not used them in combat.
Several terrorist and rebel groups have also used drones both for surveillance and to carry out attacks, including ISIS, Hezbollah, Hamas and the Houthi rebels in Yemen. The Lebanese group Hezbollah was the first nonstate actor to use military-grade drones for surveillance, and has also used armed drones in Syria.
The Palestinian group Hamas has also acquired military-grade unmanned aircrafts, while ISIS has created improvised weapons by attaching explosives to over-the-counter drone models. The Iran-backed Houthi rebels in Yemen have used unmanned vessels to attack Saudi Arabian ships.
Which countries produce armed drones?
Because of human rights concerns, until this year the United States sold its armed drones only to close allies, such as Britain, France and Italy.
This has helped enable China to become a top armed drone supplier. Israel is another leading exporter of armed drones.
China is not a party of the Missile Technology Control Regime (MTCR), which was created to limit the proliferation of missiles, missile technology, and other weapons of mass destruction. Because China has not ratified this agreement, it does not have as many restrictions for its exports, thus Chinese drone sales have boomed.
In April, the Trump administration announced a new policy to allow the sale of armed drones to more countries.
President Donald Trump said that this new policy was meant to boost sales for the American defense industry. But it will also likely mean that regulators give less scrutiny to the risk of buyers committing human rights abuses with these weapons.
The tipping point
The rapid proliferation of armed drones poses novel questions for national security.
The Chinese are testing "swarms" of drones working together powered by artificial intelligence. This kind of technology will help to reshape conventional warfare between states.
At the same time, as truck and car bombs reshaped terrorism in the 20th century, armed, crude drones in the hands of terrorist groups and even lone actors are likely to reshape terrorism in the 21st century.