"According to intelligence obtained by our side and the U.S., the possibility of a missile launch by North Korea is very high," Foreign Minister Yun Byung-se told lawmakers, adding that North Korea could launch the missile "at any time from now."
Yun said the Musudan missile has a range of 3,500 kilometers (about 2,175 miles) "and it's up to North Korea how far it would fly," South Korea's Yonhap News Agency reported.
Japan deployed missile defense systems around Tokyo, and U.S. radars and satellites honed on the area where Kim Jong Un's regime is thought to have prepared mobile ballistic missiles for a possible test launch, CNN said.
Yun said the U.N. Security Council would convene immediately if North Korea conducts a ballistic missile test.
During the parliamentary hearing, Yun said the South Korean government asked China and Russia to help try to persuade North Korea "to change its attitude."
The minister said the international community was united in dealing with "North Korea's provocative threats, nuclear test and missile launch in a consistent and resolute manner."
North Korea has made increasingly provocative threats following the U.N. sanctions against Pyongyang for conducting its third nuclear test Feb. 12. Since then, the North has threatened to launch a pre-emptive strike against South Korea and the United States, voided the Korean War cease-fire, cut off the hotline between Pyongyang and Seoul, and suspended operations at the inter-Korean industrial park in Kaesong, just north of the demilitarized zone.
U.S. Secretary of State John Kerry will be in Seoul Friday for talks with Yun.
On Tuesday, a U.S. official said that Washington believes a test launch could occur without North Korea notifying commercial aviation and maritime shipping entities to stay away from the missile's path, CNN said.
Adm. Samuel J. Locklear, the top U.S. commander in the Pacific, said during a Senate Armed Services hearing Tuesday the U.S. military would not want to shoot down a North Korean missile with a trajectory sending it into open waters. However, if the missile's path appeared to threaten a U.S. ally, interceptor missiles could be used to try to bring it down.