On Thursday, a Malaysian Boeing 777 passenger airliner carrying 295 crashed over Eastern Ukraine, where fighting between pro-Russian separatists and Ukrainian forces has raged for months. Early reports indicate that there were no survivors.

The crash comes at a time of heightened tensions, with escalating violence and threats between forces loyal to Moscow and Kiev growing increasingly heated.

In reaction to this event, CBS News national security analyst Bob Orr reported that it was highly unlikely that an aircraft traveling at cruising altitude – approximately 33,000 feet — could have suffered a mechanical failure. He added that it was more likely that this aircraft’s crash was not attributable to a mechanical incident.

“It’s extremely rare for an aircraft to come down at altitude,” Orr reported. “And when one does come down, it is usually the result of an external force, like a bomb or a missile.”

“It’s almost inconceivable to come up with a mechanical scenario that would fit the facts of an aircraft crashing from that safe phase of flight,” the analyst added.

CBS State Department reporter Margaret Brennan reported that U.S. officials are looking into the crash, but cannot determine whether claims that the plane was shot down are accurate at this time.

The Ukrainian Interior Ministry claimed that Malaysian Airlines Flight 17 was shot down. That has not yet been confirmed, but, if the aircraft began to break up in the air in a pattern consistent with having been impacted by a missile, experts indicate that the crash debris field would stretch for several miles.

There are other scenarios which may have resulted in the plane’s crash. NBC News reported on Thursday afternoon that the flight departed from normal procedure when it went into “radio silence” shortly after liftoff, which could indicate that there was an “event on board” the plane inconsistent with a missile attack.

Ukrainian reports indicate that a missile capable of taking down a plane at that altitude would have been impossible from a shoulder-fire weapon. A more sophisticated system would have to be used in that case.

While unconfirmed, this would not be the first aircraft hit by anti-air ordinance over Ukraine in recent days. On Tuesday, Interfax Ukraine reported that a Ukrainian Air Force Su-25 attack aircraft was forced to make an emergency landing after being hit by a surface-to-air missile. According to a TASS report, pro-Russian separatists also claimed responsibility for shooting down a Ukrainian AN-26 on July 14.

On Wednesday, the U.S. and its European allies imposed new sanctions on Russia after months of escalating tensions in the region. The move came as videos surfaced online featuring a missile barrage reportedly launched from Russia directed at Ukrainian positions.

UPDATE: America’s former ambassador to Russia, Michael McFaul, reports an ominous development:

CBS also reports that the debris field is several miles long, consistent with the breakup of an airliner in mid-flight.

UPDATE 1:04 p.. ET: Pro-Russian separatists are reportedly attempting to relocate MH17’s debris and flight recorders to Russia.

UPDATE: 1:26 p.m. ET: An advisor close to the Ukrainian Interior Ministry reports that 23 Americans are among those who likely died in the crash of MH17.

Tags: Russia Ukraine