Ukraine: Photos show undercover Russian troops - by Arwa Damon, Michael Pearson and Ed Payne

Do a series of photos of gun-toting men wearing green uniforms prove Russian forces are operating in eastern Ukraine?

Ukrainian officials point to the pictures in a dossier obtained Monday by CNN, arguing that the images show Russian "sabotage-reconnaissance groups" acting in Ukrainian towns.

The images, Ukrainian officials say, prove organized Russian activity in the region.

CNN cannot independently confirm the photographs, some of which were first published in The New York Times.

The dossier shows what Ukrainian officials say are images of well-equipped gunmen in eastern Ukraine who look similar to photographs of Russian forces taken in Crimea, Russia and during Russia's 2008 invasion of Georgia.

Last week, Ukrainian security officials told CNN they had arrested a Russian military officer and a woman Ukrainian officials said is a Russian intelligence agent.

Moscow has disavowed involvement in the takeover of government buildings in eastern Ukraine or other acts by often-masked pro-Russian gunmen.

Read more: Ukraine: Photos show undercover Russian troops - CNN.com