South Korea is considering its own sanctions against North Korea - Yonhap

Yonhap report says, "South Korea has begun considering its own sanctions against North Korea, along with ways to effectively and faithfully implement international sanctions imposed by the U.N. Security Council."

It adds, "the move came after a South Korean fishing boat, the 391 Hungjin, was returned to the country, reportedly after entering North Korean waters at will and being seized by North Korean troops."