SEOUL — An unmanned drone crashed on a South Korean island near a disputed maritime border with North Korea, a South Korean defense ministry official said on Tuesday, triggering an investigation into whether the aircraft was from the North.

The drone fell on Baengnyeong island at about 4 p.m. on Monday, when North Korea fired hundreds of artillery rounds in seas close to a disputed maritime line. That triggered a similar show of strength from South Korea.

The South Korean military was trying to verify where the drone had come from and what its purpose might have been, and was also looking into any possible link to North Korea's espionage operations, the military official told Reuters.

The official, who asked not to be identified, did not give any further details.

North Korea fired more than 100 artillery rounds into South Korean waters as part of a drill on Monday, prompting the South to fire back. The exercise appeared to be more sabre-rattling by Pyongyang, rather than the start of a military standoff.

Yonhap News Agency, quoting an unidentified South Korean government official, reported that the drone was 2 to 3 meters (7 to 10 ft) long and comprised a Japanese engine and Chinese parts, as well as a small camera.

Yonhap also said the drone was similar to another found in a border city late last month.

Images of the crashed drone on domestic cable news network YTN showed the wreckage of a small aircraft bearing similar paint and markings to North Korean drones displayed in a Pyongyang parade last year.

Those drones were larger target drones modified to crash into pre-determined targets, but are not believed to be capable of air strikes or long-range surveillance flights.

Small, commercially available remote-controlled aircraft can be modified to carry video cameras and other surveillance equipment.