(CNN) -- NATO has released satellite photos that show the extent of Russia's military mobilization on its border with Ukraine -- including fighter jets, tanks, artillery and thousands of soldiers who are prepared to invade within 12 hours if called upon, say officials. The photos appear to confirm Western leaders' fears that Russia may be preparing for a ground invasion of eastern Ukraine, despite NATO's call for Russia to withdraw its forces from the border. What do the photos show? The photos, which private satellite imaging firm DigitalGlobe says it took between March 22 and April 2, purportedly reveal dozens of Russian "fast jets," helicopters and infantry units that were not spotted in photos of the same areas last year.
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NATO releases satellite photos purportedly showing Russian military buildup near Ukraine
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Photos, reportedly taken just weeks ago, show jets, tanks, and troops amassing near border
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Russia says photos were taken last August -- NATO says claim is "categorically false"
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NATO official says Russia has up to 40,000 troops ready to invade Ukraine if called upon
"And as we've illustrated through the imagery, it's close to routes and lines of communications and it has the resources to be able to move quickly into @placeholder if it was ordered to do so."