“We’re seeing them use a lot more unclassified communications because their classified communications capability … for one reason or another, is not as strong as it should be,” a senior U.S. defense official, speaking on the condition of anonymity under terms set by the Pentagon, told reporters in a recent news briefing.

The Russian military possesses modern equipment capable of secure transmission, but troops on the battlefield have reached for simpler-to-use but less-secure lines because of uneven discipline across the ranks, an apparent lack of planning for conducting a sustained fight over long distances, and Russian attacks on Ukraine’s communication infrastructure that it, too, has relied on, experts say.

A European intelligence official, speaking on the condition of anonymity to discuss NATO’s battlefield assessments, said that since the invasion began in late February, there have been multiple instances of Russian commanders confiscating their subordinates’ personal phones for fear they would unwittingly give away a unit’s location.