Ukrainian National Guard troops in training gear at a camp in Sumy Oblast before the Russian attack.

The six Ukrainian National Guard troops killed at a training camp in Sumy Oblast on Wednesday were not on the front line. They were in the rear, running routine exercises. That is where Russia hit them.

Sumy Oblast shares a long border with Russia’s Kursk and Bryansk regions. It has been a frequent target for missile and drone attacks. The strike on the training facility is part of a broader Russian campaign this year against Ukrainian infrastructure and training sites. Hundreds of Ukrainian troops have been killed in such strikes since that campaign escalated.

The National Guard is not a standard military unit. It is a gendarmerie force under Ukraine’s Ministry of Internal Affairs, responsible for public security and internal defense. But since 2014, it has taken on a dual role: maintaining domestic order and supporting military operations against Russian aggression. That dual role puts Guard personnel in harm’s way even when they are training away from the front.

The Guard itself has a complicated history. It was originally established in 1991, after Ukrainian independence. Then-President Leonid Kuchma disbanded it in 2000 as a cost-saving measure. It was re-established in 2014, following the Revolution of Dignity and the start of Russian military intervention. The force has been active ever since.

Wednesday’s attack highlights a persistent vulnerability for Ukraine. Rear-area installations remain exposed. Russian forces are trying to disrupt Ukrainian force generation and logistics. Training camps, ammunition depots, and power grids are all targets. The Biden administration has provided billions in security assistance since the full-scale invasion began in 2022. But Ukrainian officials have repeatedly warned that shortages of interceptors and artillery shells leave troops vulnerable to precision strikes.

This is not a new problem. Ukraine has been pressing Western allies for additional air defense systems and long-range strike capabilities for months. The need is acute in border regions like Sumy Oblast, where missile flight times from Russian launchers can be measured in minutes. Interceptors are expensive and limited in number. Ukraine cannot defend every square meter of its territory.

The six dead are a small number in a war that has killed tens of thousands. But each loss is a loss of trained personnel. The National Guard cannot easily replace experienced troops. Training new ones takes time and exposes them to the same risks. Wednesday’s strike hit a facility where Guard personnel were conducting routine exercises. Those exercises were meant to prepare them for combat. Instead, they became the site of their deaths.

Russia’s strategy is clear. Hit the rear. Disrupt training. Slow Ukraine’s ability to generate combat power. The front-line fighting grinds on, but the war is also being fought in places like Sumy Oblast, far from the trenches. Wednesday’s attack is one more data point in that campaign.

Ukraine’s allies have not yet provided enough air defense to stop these strikes. The Biden administration has provided billions, but the flow of interceptors and shells is not unlimited. Ukrainian officials have warned that the shortages leave troops vulnerable. Wednesday’s attack proves them right.

The six dead will not be the last. Russia will keep targeting training sites and infrastructure. Ukraine will keep asking for more air defense. The war will continue on both fronts: the front line and the rear.