The National Police Agency plans to deploy anti-drone “jammers” as early as in April to prevent terrorist attacks and accidents at a slew of major events scheduled in Japan.

Tokyo’s Metropolitan Police Department is now taking the necessary procedures to gain approval from the Ministry of Internal Affairs and Communications for the use of such devices.

The jammers block radio signals between the drone and the operator in designated no-fly zones, making the unmanned aircraft unable to approach a target. The affected drones will slowly descend, return to the operator or remain stuck in one location.

The NPA included a total of about 1.4 billion yen ($12 million) in the fiscal 2018 supplementary budget and the fiscal 2019 budget for anti-drone measures.

The first big event on the calendar for the jammers will likely be Emperor Akihito’s abdication on April 30, which will mark the end of the Heisei Era, and Crown Prince Naruhito’s enthronement the following day, when the Reiwa Era will begin.

Japan will host its first G-20 summit in Osaka in late June, followed by the Rugby World Cup from September to November.

Next year, Tokyo will hold the Summer Olympics and Paralympics, starting in July.

The NPA deemed it vital to take anti-drone counter-terrorism measures to protect the crowds expected to descend on the event venues.

In April 2015, a drone operated by a man protesting the government’s nuclear energy policy was found on the roof of the prime minister’s office in Tokyo.

The MPD later introduced the nation’s first large drone designed to catch suspicious drones with a net and set up a dedicated unit to deal with unmanned aerial vehicles.

(This article was written by Taichi Kobayashi and Yohei Kobayakawa.)