The North's firing of a claimed submarine-launched cruise missile is seen in this file photo carried by North Korea's official Korean Central News Agency, Jan. 29. Yonhap

South Korea's military said Monday it is putting weight on the possibility that North Korea's latest purported test of submarine-launched cruise missiles is "exaggerated," noting that a detailed analysis is under way with the United States.

The South's Joint Chiefs of Staff (JCS) said Sunday it had detected the North's launch of several cruise missiles at around 8 a.m. over waters near the eastern port city of Shinpo, where a shipyard to build a North Korean submarine is located.

On Monday, the North's state media reported the country test-fired the submarine-launched strategic cruise missile, "Pulhwasal-3-31," with the missiles flying for 7,421 seconds and 7,445 seconds, suggesting the test involved two missiles.

"(We) are putting weight on the possibility that the North's claimed flight time is exaggerated. Further details are being analyzed by the intelligence authorities of South Korea and the United States," JCS spokesperson Lee Sung-jun told a regular briefing.

Lee declined to elaborate on the missile's launch platform, citing the ongoing analysis.

The latest launch of the Pulhwasal-3-31 came days after the North claimed to have test-fired the missile for the first time last Wednesday, although it did not provide any details of the launch at the time.

Lee said there has to be considerable technological development to launch an identical missile from a different platform, raising questions over the apparent change in the missile's launch platform in a short span of time. (Yonhap)