SEOUL - Major military officials in the Republic of Korea met Monday morning to discuss how to defend its airspace from drones dispatched by the Democratic People's Republic of Korea (DPRK), which were feared to develop into those that can conduct suicide-bombing operations, Seoul's Defense Ministry said.

The ROK's Defense Minister Kim Kwan-jin convened a meeting of major commanding officers, including chiefs of staff of army, navy and air force as well as field army commanders, to come up with measures to enhance its air defense against possible DPRK attacks with pilotless airplanes.

Defense Ministry spokesman Kim Min-seok told a routine press briefing that Minister Kim stressed the urgency of countermeasures during the closed-door meeting, noting he defined the drones as a "new threat" from the DPRK.

Pyongyang has developed such small unmanned aerial vehicles (UAV) to plug a gap in intelligence capability with the ROK, but such UAVs will advance into those that can stage terrorist attacks, the top military official said.

Minister Kim said last Friday that spy drones, believed to be sent from the DPRK, will possibly develop into those that can conduct suicide-bombing operations if Pyongyang gets to obtain advanced technology related to control systems.

The meeting of top military officials, held first this year, was called as three drones suspected of coming from the DPRK were discovered in areas close to the western and eastern frontlines in the past two weeks.

The Defense Ministry held an emergency press briefing Sunday, saying that one more drone, possibly sent by the DPRK, was found at around 11:40 am local time in Samcheok, about 290 km east of Seoul and some 130 km south of the military demarcation line between the two Koreas.

It was similar, in size and shape, to the one discovered on March 24 in Paju, the northwestern South Korean city close to the land border. Both UAVs had triangular wings and a rectangular hole, within which a small camera was carried.

On March 31 when the two Koreas exchanged artillery fire, another UAV, which the ROK suspected of coming from the DPRK, was discovered on the Baengnyeong Island just south of the disputed western sea border.

The two UAVs, spotted on Baengnyeong Island and in Paju, carried cameras, which took aerial photos of military installations and even the presidential office Blue House.

Several DPRK UAVs reportedly flew over the ROK's airspace without being recognized. Some were detected by the naked eye in frontline areas, but they were depicted as birds on the radar screen for their small size.

Spokesman Kim said that if a final conclusion is reached that those drones were flown by the DPRK, it will equal to the violation of the Armistice Agreement, which was signed after the three-year Korean War ended in 1953.

Kim said those UAVs made an illegal incursion into the ROK's airspace, adding that it will also be equivalent to the violation of related international conventions.