American intelligence agencies believe Ukrainian separatists shot down a Malaysia Airlines passenger jet by mistake, possibly by misreading fuzzy radar images on a sophisticated surface-to-air missile launcher provided by Russia, senior U.S. intelligence officials said Tuesday.
The launcher that U.S. officials believe fired the SA-11 heat-seeking missile used a rudimentary radar system that gives an incomplete picture of what is flying above, officials said. Such antiaircraft systems are designed to be linked to other radar that would allow the crew on the ground to distinguish between military and civilian aircraft.
Because separatists did not have secondary radar images available, they probably mistook the airliner for a Ukrainian military plane, the officials said.
The missile that took down the jetliner was probably fired by an "ill-trained crew," said one U.S. official who requested anonymity because he was not authorized to speak publicly on the issue. "It does appear to be a mistake."
Separatist forces have shot down at least a dozen Ukrainian military aircraft, mostly ground-attack helicopters and low-altitude jets, using shoulder-fired rockets and surface-to-air missiles, the official said.
U.S. officials have not released evidence proving that Russia's military played a direct role in the downing of the jet or in training separatists to use the SA-11 missile system.
But they said Tuesday that the Russian military has been training Ukrainian separatists to operate antiaircraft batteries at a base in southwestern Russia.
Since the crash, Russia has increased the movement of military hardware into eastern Ukraine, officials said. On Tuesday morning, U.S. intelligence agencies confirmed that about 20 tanks and armored vehicles crossed Russia into eastern Ukraine.
The Russian government is also training separatists on a "gigantic" military base near the southwestern town of Rostov, officials said. Officials shared satellite images of the base that showed a large buildup of vehicles between June and mid-July. One image was dated June 19 and the other image, which showed dozens of rows of additional vehicles, was dated July 21.
Tanks and infantry fighting vehicles from Russia have been driven into the area around Luhansk in eastern Ukraine in the last week, officials said. Officials believe that Russia stepped up its training and deliveries of military hardware in the last month because separatist forces were being pushed back by the Ukrainian military. Ukrainian troops recaptured the city of Slovyansk on July 5; it had been held by separatists since April.
U.S. intelligence agencies have so far been unable to determine the nationalities or identities of the crew that launched the missile. U.S. officials said it was possible the SA-11 was launched by a defector from the Ukrainian military who was trained to use similar missile systems.
But U.S. intelligence agencies have independently verified photos posted to social media last week that show an SA-11 launcher driving toward the Russian border missing at least one missile, the officials said.
U.S. analysts have also been able to authenticate recordings released online by the Ukrainian government of conversations between known separatist leaders after the jetliner crashed. The voices were matched with the unique sound signatures from speeches and other earlier recordings of the leaders, officials said.
Russian President Vladimir Putin has publicly embraced the separatist leaders, officials said. In speeches, he refers to the separatist forces as the "people's militia" and calls the area they hold "New Russia," officials said, based on analysis of Putin's public speeches in recent months.