Tokyo, Sep 28 (IANS): North Korea on Tuesday fired what appeared to be a ballistic missile, Japanese government officials said.

The unidentified projectile was believed to have splashed into waters outside of Japan's exclusive economic zone, the Japanese government said, Xinhua news agency reported.

According to South Korea's military, North Korea fired the unidentified projectile at around 6.40 a.m. local time into the sea off its east coast from an inland location.

Japanese Prime Minister Yoshihide Suga said that Japan will step up surveillance following the North Korean launch.

The incident followed the North Korean launch of two ballistic missiles into waters within Japan's exclusive economic zone on September 15.

The two missiles reached an altitude of about 50 km and flew around 750 km before splashing into waters off the Noto Peninsula, according to Japan's analysis.

North Korea has said the launch on September 15 was a test of a railway-borne missile system with an objective to strike a target area 800 km away.