The Democratic People's Republic of Korea (DPRK) fired a long-range rocket Friday morning, but the launch appears to have ended in failure, the South Korean defense ministry said.

The Unha-3 rocket dropped several minutes after taking off from the Tongchang-ri launch site at 7:39 a.m. (2239 GMT), the ministry said, adding the rocket broke into several pieces before falling into the sea.

Reports say the rocket seemed to have landed in waters some 200 kilometers off South Korea's western port city of Gunsan.

The DPRK announced last month it would launch the rocket-mounted Kwangmyongsong-3 satellite between April 12 and 16 to mark the centenary of late DPRK founder Kim Il Sung's birth.

Seoul and Washington, among others, see it as a disguised long-range ballistic missile test that violates a U.N. Security Council resolution.

Seoul and Tokyo have said they will shoot down the rocket if it strays into their territories, while Pyongyang warned of "merciless punishment" for such attempts.