Analysts at the CIA and other U.S. intelligence agencies are continuing to examine information about the crash, but the officials said the intelligence assembled in the five days since the attack points overwhelmingly to Russian-backed separatists in territory they control in eastern Ukraine.
The senior intelligence officials said they have ruled out the possibility that Ukrainian forces were responsible for the attack.
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Russia has gone to significant lengths to disguise that flow of weaponry, the officials said, by delivering equipment that matches the inventory of Ukraine’s military. In some cases, the officials said, Russia appears to have pulled aging and inactive tanks out of storage because shipping newer ones would make it obvious that Russian arms were flowing into Ukraine.
“We think they’re continuing to do it” in the aftermath of the strike on the Malaysian aircraft, one of the intelligence officials said.
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The U.S. officials said they have confirmed the authenticity of some of those recordings, including one in which the self-proclaimed defense minister of the Donetsk People’s Republic, Igor Strelkov, claimed responsibility for shooting down a military transport plane at the time the Malaysian aircraft was struck.
Analysis comparing that audio clip to other confirmed recordings of Strelkov’s voice “confirmed these were authentic conversations,” one of the officials said.