The Russian government has opened a new battlefront against NATO: Targeting troops’ smartphones in an effort to learn key details about upcoming or ongoing operations.

Troops, officers and government officials of North Atlantic Treaty Organization member countries said Russia has carried out a campaign to compromise soldiers’ smartphones. The aim, they say, is to gain operational information, gauge troop strength and intimidate soldiers.

U.S. and other Western officials said they have no doubt Russia is behind the campaign. They said its nature suggests state-level coordination, and added that the equipment used, such as sophisticated drones equipped with surveillance electronics, is beyond the reach of most civilians.

A probe indicated Russia had used a portable telephone antenna to gain access to phones in the area, said one officer. The device apparently grabbed data sent from mobile phones and erased information on them.

“They were stripping everyone’s contacts,” the officer said.

Officials say that Kremlin intelligence operators are especially interested in the personal communications of some 4,000 NATO troops deployed over the summer to the eastern boundaries of the alliance — in Poland and the Baltic States.

One such target: U.S. Army Lt. Col. Christopher L’Heureux, who took over as commander of a NATO base in Poland in July. He returned from the shooting range recently to find that there had been an attempt to access his iPhone from an IP address in Moscow. The hacker was attempting to get past a second layer of password protection.

“It had a little Apple map, and in the center of the map was Moscow,” said Col. L’Heureux, stationed not far from a major Russian military base. “It said, ‘Somebody is trying to access your iPhone’.”

L’Heureux, who prepares tactical troop positions to repel a potential Russian invasion, also said he was being geo-tracked via his phone. “They were geolocating me, whoever it was,” he said. “I was like, ‘What the heck is this?’”

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