(CNN) — North Korea claims it successfully test-fired new long-range cruise missiles over the weekend, according to the country’s state-run Korean Central News Agency (KCNA).

The report, dated Monday, says the country’s Academy of Defense Science successfully test-fired the missiles on September 11 and 12, and that the weapons had been in development for two years.

The weapons demonstrate “another effective deterrence means for more reliably guaranteeing the security of our state and strongly containing the military maneuvers of the hostile forces against the DPRK,” the agency said, using the acronym for North Korea’s official name, the Democratic People’s Republic of Korea.

The US and neighboring South Korea are looking into the launch claims, officials in both countries told CNN.

“Cruise missiles are often detected after the tests are conducted for their low flight altitudes. North Korea had conducted two cruise missile tests already this year, but we did not disclose them as we do not disclose all cruise missile tests we detect,” a South Korean Defense Ministry official also said.

The North Korean launch announcement comes just as South Korea’s top nuclear envoy heads to Japan to discuss North Korea with US and Japanese officials on Monday and Tuesday. China’s Foreign Minister, Wang Yi, is scheduled to visit South Korea this week as well.

The US military’s Indo-Pacific Command said it is aware of reports of cruise missile launches from North Korea, and that the US is working with allies and partners.

“This activity highlights DPRK’s continuing focus on developing its military program and the threats that poses to its neighbors and the international community,” the Indo-Pacific Command said in a statement.

‘Totally expected’

Multiple UN Security Council resolutions have expressed concern about North Korea’s ballistic missile program. However, such resolutions have not focused on the development or testing of cruise missiles.

Unlike ballistic missiles, cruise missiles are propelled by jet engines. Much like an airplane, they stay closer to the ground, making them harder to detect. Most cruise missiles are not designed to carry nuclear warheads, either.

However, this missile test was the most significant from North Korea since US President Joe Biden took office in January.

According to KCNA, the new missiles traveled for 7,580 seconds along oval and figure-eight flight orbits in the air above the territorial land and waters of North Korea and hit targets 1,500 kilometers (930 miles) away.

“This is a system that can reach targets throughout Japan,” said Jeffrey Lewis, a professor at the Middlebury Institute of International Studies who specializes in open-source intelligence, “whereas the system we saw in March was a shorter range system just to target South Korea.”

Lewis was referencing a series of North Korean missile tests earlier this year where Pyongyang test-fired a missile that flew 450 kilometers.

“It’s a technical achievement for them,” Lewis told CNN, but added that the test was “totally expected.”

“It was very clear they were going to test something, and this was clearly on the list,” he said.

North Korea’s earlier test launches this year were widely seen as attempts to send a message to the Biden administration about the isolated country’s importance in the region.

North Korea has shown off new and untested weaponry in its military parades over the last few months. The US anticipated that some of this would eventually be tested in a show of strength by North Korea and its leader, Kim Jong Un.

The North Korean leader’s sister, Kim Yo Jong, had warned last month that the country would respond to joint military exercises between the US and South Korea, which would “face a more serious security threat” for ignoring repeated warnings against the drills.

Late last month, the US also approved the sale of $258 million of precision guided munitions and related equipment to South Korea.

And South Korean media reported last week that the South Korean Navy tested-fired a ballistic missile from a submarine for the first time. The country’s Defense Ministry declined to confirm or deny those reports.

The-CNN-Wire™ & © 2024 Cable News Network, Inc., a Time Warner Company. All rights reserved.

Join our Newsletter for the latest news right to your inbox