The Democratic People's Republic of Korea has unsuccessfully launched three mid-range missiles this week. South Korea suspects there may be internal pressure over at the DPRK to conduct missile launches, as the upcoming Worker's Party congress looms.

"There could be external factors that affect the DPRK carrying out the consecutive launches of Musudan ballistic missiles. However, it seems that ahead of the Worker's Party congress, the North re-launched ballistic missiles within a short period of time, under pressure, with DPRK leader Kim Jong Un's order.

It is perceived that there's also a situation in which Kim's government needs to make some achievements ahead of the party congress," said Jeong Joon-hee, spokesperson of South Korean Unification Ministry.

The South Korean military said there is a possibility that the DPRK will launch another missile. Seoul will remain on high alert. South Korean President Park Geun-hye said the DPRK wants to be recognized as a nuclear state -- but stressed the international community will never acknowledge that.