SEOUL — North Korea has test-fired two types of submarine-launched strategic cruise missiles, state news agency KCNA said today. 

The agency said the missiles were fired Wednesday into the East Sea, also known as the Sea of Japan, without “any adverse impact on the security of neighboring countries”.

The reported launch came after weeks of mounting friction over a landmine explosion along the heavily fortified border between North and South Korea.

Three South Korean soldiers were injured in the September 21 blast in the Seoul-controlled area of the Demilitarised Zone (DMZ), with both countries testing upgraded missile technology in the aftermath.

The latest testing “aimed to examine the current mobilized posture of the underwater combat systems” and served as a Navy training exercise, KCNA said.

The tests showed the “high reliability, trustworthiness and ability of the war deterrents of the DPRK,” the agency reported, referring to North Korea by the abbreviation of the country’s official name.

Photos released by KCNA showed one missile blasting vertically out of the sea trailed by a thick plume of smoke. Another photo appeared to show a projectile erupting from the water at a 45-degree angle.

Other images showed a missile flying horizontally over the sea, as well as a submarine traveling on the water’s surface.

North Korea has carried out several missile launches from submarines in recent years, although its sea-based launch capabilities remain unclear.

Cruise missiles tend to be jet-propelled and fly at a lower altitude than more sophisticated ballistic missiles, making them harder to detect and intercept.