Yandex Maps, Russia's most popular web mapping service, has inadvertently revealed the exact locations, perimeters, and potential functions of hundreds of military facilities in Israel and Turkey, as well as two major NATO bases, according to Matt Korda of the Nuclear Information Project at the Federation of American Scientists (FAS).

The secret military sites on Yandex Maps range from airfields and munitions-storage bunkers to what Korda characterized as "small, nondescript buildings within city blocks."

Blurring out specific sites is unusual, said Korda, adding that it was certainly done at the request of both Israel and Turkey.

“Mapping services like Yandex typically play a reactive role in these cases, as they are responding to requests from outside sources to obscure a pre-defined list of sites,” Korda told Quartz. “Since no Russian sites have been blurred, I would assume that the Russian Ministry of Defense hasn’t asked Yandex to do so.”

“Our mapping product in Israel conforms to the national public map published by the government of Israel as it pertains to the blurring of military assets and locations,” a Yandex spokesperson told Quartz. “Our Turkish map product observes local rules and regulations similarly.”

When comparing the blurred sites with images from Google Earth, the analyst said he was able to identify military bases, including large airfields, ports, bunkers, small buildings in metros that are not marked by Google. Some of the sites were top secret, in total, Korda found about 300 of these places.

"Included in the list of Yandex's blurred sites are at least two NATO facilities: Allied Land Command (LANDCOM) in Izmir, and Incirlik Air Base, which hosts the largest contingent of US B61 nuclear gravity bombs at any single NATO base", he said, adding that no Russian facilities have been blurred, including "its nuclear facilities, submarine bases, air bases, launch sites, or numerous foreign military bases in Eastern Europe, Central Asia, or the Middle East".

Korda added that the entire country of Syria is depicted in "extremely low resolution, making it nearly impossible to utilize Yandex for analyses of Syrian imagery."

According to the analyst, Google Earth heavily censors military sites at the request of governments that want to "keep prying eyes away from some of their more sensitive military or political sites."

Earlier this year, San Francisco based fitness company Strava posted their "global heat map" to their website, containing two years worth of fitness data across several fitness devices such as Jawbone and Fitbit, had revealed the location, staffing, patrol routes and layout of U.S. and foreign military bases around the world.

By complying with requests to obscure military bases, Yandex has revealed hundreds of secret Israel and Turkey military bases.