A small vessel carrying seven North Koreans was discovered in the Yellow Sea on Monday. The South Korean military has launched a probe to determine whether it is a defection.

A South Korean fishing boat found the North Korean vessel 17 miles west of Deokjeok Island near Incheon on Monday afternoon. Seven North Koreans, all men, were on board.

The Korea Coast Guard towed the vessel to Incheon Port, after which a joint probe team comprised of the military and the National Intelligence Service began questioning the men to determine their intent.

North Korea said Monday that it was planning to set a "peacetime firing zone" along the inter-Korean border, raising tension in the volatile Yellow Sea region. The South Korean Navy has warned of a stern response.

Earlier on October first, a three-ton fishing boat carrying eleven North Koreans defected to the South via the East Sea.