Flashes were observed by an American military satellite in the vicinity of a Russian plane that crashed in Egypt over the weekend, but officials cautioned that it was too early to tell what they were, or even if they were connected to the plane.
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A defense official said there were flashes picked up by satellite infrared sensors -- designed to detect missile launches -- around the same time that the plane was passing over the Sinai Peninsula.
The official said that if the flashes are connected to the aircraft, it might indicate that something happened in the air or by the plane's impact on the ground. But there was military activity in the area, so they may not be related, the official said.
According to the official, a missile strike was unlikely because no trail was detected by satellite.
Meanwhile, an official for the Russian company said the crash could only have been caused by a “mechanical impact” on the plane.
Although the plane's black boxes are still being analyzed, Alexander Smirnov, deputy general director of Russian airliner Metrojet, insisted that the Saturday crash could not have been caused by a technical fault.
"The only explicable cause can be a mechanical impact on the aircraft," Smirnov said, adding "there is no possible combination of system failures that could lead to the aircraft breaking-up in mid-air.
"The plane's crew completely lost control over the aircraft as the disaster started to unfold," Smirnov added.
Egyptian officials say there was no distress call.
ABC News aviation consultant Col. Stephen Ganyard, a retired Marine fighter pilot, said it’s too early to rule out anything. “We don’t have any evidence that points us in one way or the other,” he told “Good Morning America” today.
The head of Russia's Inter-state Aviation Committee investigating the crash told journalists in Cairo Sunday that the plane broke up in midair, but warned that it was "too early to state a cause for the plane's destruction."
Russian state media reports that 140 bodies were transported today to St. Petersburg where they will be identified by family members.
Three days of mourning have been declared in Russia in honor of the victims.