This picture taken on October 19, 2021 and released from North Korea's official Korean Central News Agency (KCNA) on October 20, 2021 shows test fire of a new type submarine-launched ballistic missile in an undisclosed location in North Korea. (Photo by various sources / AFP) / South Korea OUT / ---EDITORS NOTE--- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO/KCNA VIA KNS" - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS / THIS PICTURE WAS MADE AVAILABLE BY A THIRD PARTY. AFP CAN NOT INDEPENDENTLY VERIFY THE AUTHENTICITY, LOCATION, DATE AND CONTENT OF THIS IMAGE --- /  (Photo by STR/AFP via Getty Images)
Explained: How much damage can North Korea's weapons do?
02:53 - Source: CNN
Seoul, South Korea CNN  — 

North Korea’s launch last week of an intercontinental ballistic missile (ICBM), reported to be its most formidable yet, may have been a less advanced weapon than previously believed, according to a South Korean military official.

The official, who spoke under the condition of anonymity, said South Korean and US analysis of the March 24 launch of what North Korea claimed was a new Hwasong-17 ICBM, was in actual fact the older and slightly smaller Hwasong-15 – an ICBM last tested by Pyongyang in 2017.

Several missile experts have since reached a similar conclusion, but they caution the significance of last week’s successful ICBM launch – North Korea’s first in more than four years – should not be discounted, pointing out the test still demonstrated a weapon with the theoretical ability to hit all of the continental United States.

The ICBM fired by North Korea last Thursday flew to an altitude of 6,000 kilometers (3,728 miles) and to a distance of 1,080 kilometers (671 miles) with a flight time of 71 minutes before splashing down in waters off Japan’s western coast last Thursday, according to Japan’s Defense Ministry.

Japan’s Vice Defense Minister Makoto Oniki told reporters shortly afterward that the missile’s altitude would suggest it is a “new type of ICBM.”

Japanese officials were sticking to that assessment this week, with Chief Cabinet Secretary Hirokazu Matsuno saying on Monday that Tokyo judged the missile to be a new type based on flight altitude and other information.

And CNN previously reported that the Pentagon is still assessing to what extent the missile is an improved version of previous launches.

But the South Korean official and missile experts said further close analysis of images in North Korean state media of last week’s launch gave two potential clues relating to Pyongyang’s alleged subterfuge.

The South Korean official said assessments by Seoul and Washington showed the ICBM launched last week only had two engine nozzles, like Hwasong-15, whereas Hwasong-17 has four.

This picture from North Korean state media, purportedly taken on March 24, shows leader Kim Jong Un walking with North Korean military personnel during the test launch operation of what state media reported was a new type intercontinental ballistic missile.

And video released last Friday by state-run Korean Central Television (KCTV) purporting to show Kim Jong Un guiding the launch reveal the North Korean leader’s shadow appearing westward, meaning it was filmed in the morning, but the launch took place in the afternoon, the official said.

Also, it was cloudy in the launch area last Thursday, but the weather in the KCTV video appears to be sunny, the official said.

Analysts say US must still be wary

Several missile experts have also begun to cast doubt on North Korea’s claim to have launched a Hwasong-17.

Jeffrey Lewis, director of the East Asia Nonproliferation Program at the James Martin Center for Nonproliferation Studies, said the KCTV video appears to have been made during a failed launch on March 16, in which a North Korean missile exploded soon after liftoff around an altitude of 20 kilometers (12.5 miles).

“North Korea released a video after the March 24 test. We measured the shadows in it, however, and it is clear from the altitude and angle of the sun that the video is from the test on the morning of March 16,” Lewis said.

“The video is of the (previous) test that failed. That strongly suggests the other test was something different that they don’t want us to see.”

Ankit Panda, a nuclear policy expert at the Carnegie Endowment for International Peace, said Pyongyang may have altered the Hwasong-15 – first tested nearly five years ago – to make it look like a more powerful missile.

This picture released by North Korean state media on March 25 claims to show the launch of a new intercontinental ballistic missile. South Korea and missile experts dispute its authenticity.

“They claimed that it’s the Hwasong-17, which is the new, very large ICBM they inaugurated at a parade in October 2020, but it looks like what they actually did was they put a very light or perhaps no payload on a Hwasong-15, which is the ICBM they first tested in November 2017. And they used that to stage a demonstration,” Panda said.

Panda said Pyongyang’s apparently inflated claim was aimed at a domestic audience rather than internationally.

“The only thing going well in North Korea right now is the missile program, so perhaps Kim Jong Un plans to use this demonstration to indicate to his own people that they are suffering, the food shortages, the economic difficulties, the lockdown over Covid, that all of this has been worth it, because their national defense capabilities are still advancing,” he said.

On Tuesday, South Korean lawmaker Ha Tae-keung told reporters that, according to a military briefing, debris rained down over the North Korean capital, Pyongyang, following the failed March 16 test.

This picture by North Korea's official Korean Central News on March 25 purportedly shows leader Kim Jong Un walking near what state media reported was a new type intercontinental ballistic missile. Experts doubt the claims.

Ha’s office confirmed the lawmaker’s remarks to CNN on Thursday, adding North Korea may have been prompted to announce the March 24 Hwasong-15 launch as a Hwasong-17 to temper negative opinions in Pyongyang, where citizens witnessed the March 16 failure. North Korea has not acknowledged reports of a failed March 16 test.

Lewis, the nuclear weapons expert, said regardless of which missile was fired last Thursday, the test showed a powerful offensive capability that US defense officials have to be wary of.

“The missile fired on March 24 would have had a range of about 12,000 kilometers (7,500 miles), which is certainly within the capability of a Hwasong-15, which can deliver a nuclear weapon anywhere in the United States,” Lewis said.

And Matsuno, the Japanese official, said Monday that North Korea’s missile program remains a serious threat to the security of Japan, the region and the world.

CNN’s Yoonjung Seo and Junko Ogura contributed to this report.