Russia is hacking the smartphones of NATO troops in Europe in a cyber campaign to gauge ​military strength, gain insight into operations and intimidate soldiers, according to a report Wednesday.

US and Western officials say they have no doubt the Kremlin is behind the hacking operation because of its high level of coordination and its use of sophisticated drones with surveillance equipment that are beyond what civilians can acquire, the Wall Street Journal reported.

The electronic eavesdropping operation is targeting a contingent of about 4,000 NATO troops​ ​stationed in Poland and the Baltic states to guard the organization’s European border with Russia, the report said, citing Western military officials.

​One of the soldiers hacked, US Army Lt. Col. Christopher L’Heureux, who prepares tactical troop positions ​to defeat a Russian invasion, said he discovered his phone had been hacked and reported lost when he returned to his truck from shooting drills this summer.

​The hacker, he said, was trying to ​break through another layer of password protection via a Russian IP address.

​​“It had a little Apple map, and in the center of the map was Moscow,” L’Heureux​ told the newspaper. ​“It said, ‘Somebody is trying to access your iPhone​.​’”​

He also learned that somebody was physically tracking him though his smartphone.

“They were geolocating me, whoever it was,” he said. “I was like, ‘What the heck is this?’”

The Russian Defense Ministry didn’t respond to a request for comment.

W​estern officials said infiltrated cellphones could be used to create confusion on the battlefield and slow NATO’s response to an invasion by sending out false instructions.​

A compromised phone, they said, could even be used to pick up sensitive information if a soldier brought it into a military command post.

The hacking was first noticed in January when soldiers stationed near Estonia’s border with Russia began complaining of “strange things” happening with their phones at the Tapa military base, the report said.

An investigation revealed Russia had been using a portable antenna to access phones in the region. The device snatched data sent from cellphones and erased information on them.

​“They were stripping everyone’s contacts,” ​one officer told the Wall Street Journal.​

An Estonian soldier stationed on the Russian border in March said his phone suddenly started playing hip-hop music that he hadn’t downloaded and his contacts began disappearing from his phone.

After the incidents in January, soldiers at the Tapa base have been told to remove the SIM cards from their phones and use the internet only at designated spots. They are not allowed to use location services.

“Russia has always sought to target NATO servicemen for intelligence exploitation,” Keir Giles, an associate fellow at Chatham House’s Russia and Eurasia Program​, told the newspaper​. “But such a campaign of harassment and intimidation is unprecedented in recent times.”