"The break-up of a Russian passenger jet in mid-flight over the Sinai peninsula was not caused by malfunction or pilot error..."

"... the airline said Monday, deepening the mystery over the disaster but leaving open probes into some kind of plot or attack."

... Alexander Smirnov, deputy general director of the airline, insisted the tragedy could only be the result of some “mechanical impact on the aircraft.”... He declined to elaborate on the theory of an “impact.”