The missile launch comes after the North fired off two Rodong missiles and a shorter-range Scud missile on July 19.

In July, South Korea and the United States decided to deploy the Terminal High Altitude Area Defense system in the southern county of Seongju by end-2017 in a bid to counter North Korea's evolving nuclear and missile threats. The county is located about 296 kilometers southeast of Seoul.

As an integral part of the U.S.-led missile-defense system, THAAD is designed to shoot down a ballistic missile at altitudes of 40 to 150 km in its terminal phase of flight using a hit-to-kill method.

In response to Seoul's decision to deploy a THAAD battery, North Korea warned last month that it will take "physical counter-action" to deal with the anti-missile shield.

North Korea has ceaselessly developed its nuclear weapons and missiles in defiance of international condemnation. The North has fired off ballistic missiles while claiming that it had succeeded in developing a nuclear warhead small enough to be put on a missile.

It also claimed the successful launch of the Musudan intermediate-range ballistic missile in June, saying that it has the capacity to strike U.S. forces in the Pacific region.

Since North Korean leader Kim Jong-un took office in late 2011, North Korea is believed to have test-fired 32 ballistic missiles including six Musudan missiles and six Rodong missiles so far, according to Seoul's military.

The Musudan missile, with an estimated range of some 3,000 to 4,000 kilometers, could theoretically reach any target in Japan and fly as far as the U.S. territory of Guam.

The Scud missile has a range of about 300 to 1,000 km while the Rodong missile is capable of flying some 1,300 km. (Yonhap)