The exercise on Thursday involved an apparently operational strategic cruise missile unit of the Korean People’s Army, which fired the four “Hwasal-2” missiles in the area of Kim Chaek City, North Hamgyong Province, towards the sea off the east coast of the Korean Peninsula, state news agency KCNA said.

Other units conducted firepower training at hardened sites without live firing, it added.

The four strategic cruise missiles hit a preset target after travelling the “2000 km-long elliptical and eight-shaped flight orbits for 10,208 seconds to 10,224 seconds,” the English-language report said.

The drill demonstrated “the war posture of the DPRK nuclear combat force bolstering up in every way its deadly nuclear counterattack capability against the hostile forces,” said KCNA.

The missiles were not announced by South Korea or Japan, which often detect and publicly report North Korean launches.

U.S. and South Korean officials took part in a tabletop, or simulated, exercise that focused on the possibility of North Korea using a nuclear weapon, the Pentagon said on Thursday.

North Korea has forged ahead steadily in developing and mass-producing new missiles, despite sanctions imposed by UN Security Council resolutions that ban the nuclear-armed country’s missile activities.

Many launches, including an intercontinental ballistic missile (ICBM) on Saturday, have been reported by state media as drills designed to improve the capabilities of the troops operating the weapons.

“These demonstrations might be considered missile exercising rather than developmental testing,” the U.S.-based Center for International and Strategic Studies said in a report this week.

North Korea could test-fire ICBMs on a lower, longer trajectory and conduct its seventh nuclear test this year to perfect its weapons capabilities, South Korean lawmakers said on Wednesday, citing intelligence officials.