SEOUL: North Korea has begun testing its largest intercontinental ballistic missile (ICBM) system yet, U.S. and South Korean officials say, and may soon conduct a full ICBM launch for the first time since 2017.

Officials in Seoul and Washington say launches on Feb. 27 and March 5 involved the Hwasong-17 ICBM system, though they did not test its full capability or range.

North Korea did not disclose which types of rockets were used in those launches, but said they were testing components of a developmental spy satellite system.

Here's what we know about what analysts have called a "monster missile":

North Korea first unveiled the previously unseen ICBM at an unprecedented predawn military parade in October 2020, with analysts noting it appeared "considerably larger" than North Korea's last new ICBM, the Hwasong-15, which was test fired in November 2017.

It was displayed a second time at a defence exhibition in Pyongyang in October 2021. After examining photos of the exhibit, analysts concluded the official designation of this large ICBM is most likely “Hwasong-17”, not Hwasong-16.

It is unclear whether the Feb. 27 and March 5 test-fires used all or part of the two-stage missile. Some analysts say the tests may have involved only one stage.

The Hwasong-17, which has been shown on a transporter vehicle with 11 axles, would be one of the largest road-mobile ICBMs in the world if it becomes operational.

Its diameter is estimated to be between 2.4 and 2.5 meters, and its total mass, when fully fuelled, is likely somewhere between 80,000 and 110,000 kg, according to 38 North, a U.S.-based programme that monitors North Korea.

The Hwasong-17's large size has prompted analysts to speculate that it will be designed to carry multiple warheads and decoys to better penetrate missile defences. Some observers said that the satellite technology that North Korea claimed to have tested in the two launches could also be used for a multiple independently targetable reentry vehicle (MIRV) system, potentially allowing a single missile to drop nuclear warheads on different targets.