Why the World Must Confront Russia Over the Double-Tap Strike on Sumy, a Tactic Repeatedly Used in Ukraine

The KN-23 ballistic missiles (Hwasong-11Ga) are externally very similar to Russia’s Iskander-M, sharing comparable characteristics and range. Like the Iskander-M, the North Korean KN-23 follows a quasi-ballistic trajectory, stabilizing at an altitude of around 50 km. These missiles are equipped with warheads weighing about 500 kg.

The first missile, carrying a high-explosive fragmentation warhead, deliberately targeted civilian infrastructure. Notably, Ukraine’s Human Rights Ombudsman, Dmytro Lubinets, reported that the regional Human Rights Protection Center in Sumy was the primary target of the April 13 Russian missile strike. A short time later, as rescuers and medics began assisting the injured, another missile with a cluster warhead was launched. The explosion’s epicenter was a trolleybus full of people, many of whom were killed.

Cluster warheads in Iskander-M/KN-23 type missiles are designed to inflict maximum casualties over a wide area. Their fragmentation submunitions detonate about 10 meters above the ground.

Surviving such an explosion—even inside a car—is nearly impossible. Thousands of specially designed fragments capable of piercing metal, windows, doors, and fences leave no chance of escape.

The missile strike on Sumy is an example of the "double tap" tactic, which Russia has employed since the beginning of its full-scale invasion. Double missile strikes are a brutal warfare tactic where the second strike intentionally targets first responders and civilians rushing to aid victims of the initial attack—groups protected under the Geneva Conventions. Under international law, this constitutes an act of terrorism. The double tap tactic often involves a reconnaissance drone in the area to monitor the impact and aftermath.

Russia has previously conducted double strikes in Odesa, Zaporizhzhia, Kherson, Bakhmut, and Pokrovsk.

The consequences of such attacks demand increased international attention. In 1945, the Nuremberg Tribunal Charter defined the killing of civilians as a war crime and a violation of the laws and customs of war.

The list of war crimes that constitute grave breaches of the Geneva Conventions of August 12, 1949, includes: willful killing, inflicting serious bodily harm, and unlawful, wanton, and widespread destruction not justified by military necessity (Article 50 of Geneva Convention I, Article 51 of GC II, Article 130 of GC III, Article 147 of GC IV).

Additional Protocol I of 1977 expands this list to include indiscriminate attacks affecting civilian populations or civilian objects, when it is known that such attacks will cause excessive civilian deaths or injuries.

Since 2022, NAKO has been researching weapons from Iran, Russia, and North Korea used against Ukraine—specifically how Western microelectronics, particularly from the US and Europe, contribute to the production of this deadly technology. NAKO has examined Iskander-M and KN-23 missiles in multiple studies.

Therefore, we urge the international community to focus not only on the missile attacks deliberately aimed at maximizing casualties, but also on the missiles themselves, which continue to incorporate Western-manufactured components. You can read more in our thematic reports on foreign components in the DPRK-produced KN23/24 missiles and Western-made components in Russia’s war against Ukraine more broadly.

One more important detail: Russia attacked Sumy immediately after the meeting between US President's special envoy Steve Witkoff and Russian President Vladimir Putin in St. Petersburg—a show of blatant disregard for all previous negotiations and agreements.