OKINAWA, JAPAN — The United States and Japan have both deployed "nuke sniffing" aircraft following North Korea's sixth and most powerful nuclear test.

On September 3, the DPRK conducted a weapons test at the underground Punggye-ri Nuclear Test Facility, with the explosion resulting in a 6.3 magnitude earthquake.

According to Stars and Stripes, a U.S. WC-135 Constant Phoenix was deployed from Offutt Air Force Base in Nebraska, landing at Okinawa's Kadena Air Base on September 5.

Commonly referred to as a "nuke sniffer", the aircraft uses external flow-through devices to collect air particles on filter paper, measuring them onboard for radioactivity.

The nuke sniffers are also equipped to collect whole air samples inside holding spheres, to be analyzed later on the ground.

The North's nuclear test likewise prompted Japan to send three T-4 jets to collect dust and air samples for radiation testing.

Japanese C-130 transport planes will also be checking for airborne radioactive gases, though the risk of the underground tests releasing toxic radiation is generally low, according to 9news.