South Korea found a suspected third North Korean drone on a mountain on the east coast, officials said Sunday, in what could be the latest in a series of border incursions by North Korea's spy drones.

South Korean soldiers found the crashed drone in the middle of a mountain in Samcheok, 290 kilometers east of Seoul, on Sunday after three local residents informed the military that they had seen a crashed unmanned drone in the mountain in October, the defense ministry officials said.

The residents told the military they were climbing the mountain to pick medicinal herbs.

The appearance of the drone is identical to the one found in Paju, a South Korean western city near the heavily fortified inter-Korean border, on March 24, according to the officials.

South Korea found two North Korean drones in recent weeks -- one in Baengnyeong Island near the tense western maritime border and another in Paju. 

The drone discovered in Paju on March 24 was found to contain photos of military installations and the residential quarters of Seoul's presidential compound.

South Korea's Joint Chiefs of Staff said it will take legal and military actions over the North's violation of its airspace if the latest drone is found to have come from the North.

The JCS did not elaborate on what it meant by legal and military actions against the North.

The defense ministry also said it will hold a meeting of major commanding officers on Monday to discuss how to deal with North Korea's drones. (Yonhap)