The Democratic People's Republic of Korea (DPRK) fired an "unidentified projectile" off its eastern coast on Tuesday, according to the Joint Chiefs of Staff (JCS) of the Republic of Korea (ROK), hours before the ROK was scheduled to launch a new submarine equipped with ballistic missiles.

A Japanese defense ministry spokesman told AFP on condition of anonymity that the projectile "appears to be a ballistic missile." Jiji News, citing a government source, said the missile possibly landed in Japan's Exclusive Economic Zone (EEZ).

The launch is the latest in a series of mixed messages from the DPRK, coming days after leader Kim Jong Un's sister Kim Yo Jong, a key advisor to her brother, condemned the "double standards" of the ROK and the U.S. on DPRK's military development.

Moments after the JCS claimed that the DPRK had fired an "unidentified projectile" into the sea, DPRK's ambassador to the United Nations Kim Song told the General Assembly that "nobody can deny" the country's right to test weapons.

"Nobody can deny the right to self-defense for the DPRK to develop, test, manufacture and possess the weapon systems equivalent to the ones which are possessed or being developed by them," Kim said.

"We are just building up our national defense in order to defend ourselves and reliably safeguard the security and peace of the country," he added.

On Tuesday, the ROK's Navy and the Defense Acquisition Program Administration (DAPA) said the country will launch its third homegrown 3,000-tonne submarine equipped with ballistic missiles.

A launch ceremony for the 3,000-tonne-class Shin Chae-ho submarine, the third and final of three Changbogo-III Batch-I submarines, will be carried out later in the day at the shipyard of Hyundai Heavy Industries in the southeast city of Ulsan.

The third submarine would be delivered to the Navy in 2024 after sea trial. All of the three submarines are capable of firing submarine-launched ballistic missiles (SLBM) with six vertical launch tubes.

(With input from Reuters, AFP, Xinhua)

(Cover: File photo of a ballistic rocket launching drill of Hwasong artillery units of the Strategic Force of the Korean People's Army. /Reuters)