The Pentagon has said it is investigating the leak, and three U.S. officials told Reuters on Friday that Russia or pro-Russian elements are likely behind the leak of several classified U.S. military documents posted on social media that offer a partial, month-old snapshot of the war in Ukraine.The Justice Department said the documents appeared to have been altered to minimize the number of casualties suffered by Russian forces, though they cautioned that their evaluations were unofficial and unrelated to the leak investigation.Due to the sensitivity of the matter, the...