Ukrainian government officials say Russian-backed rebel forces shot down a Malaysian Airlines flight with 295 passengers and crew over the embattled border region on its way from Amsterdam to Kuala Lumpur. The commercial flight was cruising at 33,000 feet, making it too high for a shoulder-launched missile and more likely that it was targeted by a radar-guided missile defense system, according to military experts.

“It does seem depressingly likely,” said Mark Galeotti, a professor of global affairs at New York University currently studying Russian security issues in Moscow. “We know the rebels have the Buk missile system.  We know they have shot down planes in the past. They may have believed it was a legitimate target.”

Anton Geraschenko, an adviser at the Ukraine Interior Ministry, said on his Facebook page that the airplane had been hit by a Buk antiaircraft system. He also wrote that people in eastern Ukraine who support the central government had reported seeing a Buk system in the area, according to The New York Times.

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The aircraft came down about 10 miles from the Russian border. Among the dead are at least 23 Americans, according to news reports quoting Ukrainian government officials.

The Buk is a Russian-built air defense system that uses its own radar to acquire up to 24 targets at a time, and launch up to eight missiles. These missiles are built to defend against incoming aircraft, drones, missiles or guided munitions, according to Paul Schwartz, senior fellow at the Center for Strategic and International Studies in Washington and an expert in the Russian military.

“These missiles are fast, very maneuverable, and are really designed to strike highly maneuverable aircraft,” Schwartz said. “Taking out a jetliner wouldn’t have been a major problem for it.”

Even though the Malaysian Airlines flight was carrying a transponder that identified it as a civilian aircraft, Schwarz and others say the Buk missile defense system takes proper training in order to distinguish between friend and foe.

A picture taken on July 17, 2014 shows the wreckage of the malaysian airliner carrying 295 people from Amsterdam to Kuala Lumpur after it crashed, near the town of Shaktarsk, in rebel-held east Ukraine. DOMINIQUE FAGET/AFP/Getty Images

A transponder failure of some kind may have contributed to the disappearance of Malaysian Airlines flight 370 earlier this year en route from Kuala Lumpur to Beijing. That flight and its 239 occupants were lost somewhere over the Indian Ocean and have not been found.

Schwartz said that it may take some time for aviation investigators to figure out what happened since the plane crashed in a conflict zone that is not controlled by the government. However civilian and military radar data should be able to quickly determine the origin of any missile.

“There’s always a risk when you provide this equipment to an insurgent force,” Schwartz said, “which is why are reluctant to provide them to the Syrian rebels.”

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Loren Thompson, executive director of the Lexington Institute, a non-profit think tank on security issues, noted that the operator of the missile system probably made a mistake.

“A flight profile of a 777 would not have looked like a combat aircraft, but maybe the separatist didn’t know that,” Thompson said.

Even if the radar operator were trained, he may have misinterpreted data, according to Ted Postol, an expert in missile defense systems and professor at the Massachusetts Institute of Technology.

"Although the information is there to see, if you are scared and under pressure, you may misunderstand what is happening," Postol said. "If the operator is an novice he may not know what he’s looking at. You know what buttons to push, but not much else."

The experts agreed that if an international investigation finds the rebels to blame, it will be difficult for Russian President Vladimir Putin to continue providing military and financial support for the Ukrainian separatists.

“The Russians first instinct will be to point the finger somewhere else,” Galeotti said from Moscow. “But I think very soon they will realize they can’t do this as a long-term strategy.”