North Korea fired at least one ballistic missile on Monday, the South Korean military said, just hours after a separate late-night launch of a short-range missile. 

"North Korea fires unidentified ballistic missile towards the East Sea," Seoul's Joint Chiefs of Staff said, referring to the body of water also known as the Sea of Japan. 

The Japanese government said on X, formerly known as Twitter, that North Korea fired "what appears to be a ballistic missile", without giving further information. 

The launch comes after South Korea said it had detected a short-range ballistic missile launched from the Pyongyang area late Sunday night. 

That missile flew around 570 kilometers (354 miles) before landing in the East Sea, the JCS said, adding that Seoul, Washington, and Tokyo have "closely shared information regarding North Korea's ballistic missile."

North Korea last year declared itself an "irreversible" nuclear power and has repeatedly said it will never give up its nuclear program, which the regime views as essential for its survival.

And last month Pyongyang successfully put a military spy satellite into orbit. It has since claimed its eye in the sky was already providing images of major US and South Korean military sites.