The U.S. has flown a reconnaissance aircraft to South Korea to monitor North Korea's actions as tensions rise on the peninsula and Pyongyang threatens military action.

According to aviation tracker site "No callsign" on Saturday, the U.S. Air Force's E-8C Joint STARS aircraft took off from Kadena Air Base in Okinawa, Japan at 7:37 p.m. Friday.

The E-8C flew over South Korea from 9 p.m. on Friday until the early hours of Saturday, with its location tracking device turned on.

Equipped with a surveillance and target attack radar system, the E-8C can monitor North Korean ground troops and the movement of equipment from eight to 12 kilometers above ground.

On Thursday, the U.S. flew its RC-135W surveillance aircraft over Seoul and Gyeonggi Province.