The first bodies from Russia's deadliest air disaster arrived in St. Petersburg for identification as officials refused to rule out terrorism as the cause of the crash.
The Metrojet-operated Airbus A321 crashed Saturday in Egypt's Sinai peninsula, killing all 224 on board. The local ISIS affiliate claimed responsibility for shooting it down — but officials dismissed that as impossible by saying the militants lacked the weapons to do so.
U.S. Director of National Intelligence James Clapper told a "Defense One" conference Monday that there was not yet any "direct evidence of terrorist involvement" in the crash.
Still, several airlines have altered their flight paths over the Sinai peninsula pending further clarity on what caused the crash.
A Russian official said Sunday that it appeared the plane had broken up in midair — fueling speculation of a possible plot involving explosives — and officials on Monday did little to dispel those fears.
Related: Why Would Plane Break Up in Midair? Here Are 3 Scenarios
When asked whether a terror attack could have downed the plane, Kremlin spokesman Dmitry Peskov said no theory could be ruled out, according to Reuters.
Metrojet's deputy general director Alexander Smirnov told reporters in Moscow that the plane lost speed right before the crash and that no technical fault could have caused the plane to break up in the air, saying it had to be due to "an external impact on the plane."
He added that the plane dropped 186 mph in speed and 5,000 feet in altitude one minute before it crashed.
Smirnov's remarks were met by skepticism from the head of the Russian Federal Aviation Agency, who said investigators don't yet have enough data to reach that conclusion.
Aviation agency chief Alexander Neradko said in televised remarks in Cairo that it was premature of Metrojet to comment on the possible cause, according to The Associated Press.
The aircraft in question was deemed airworthy as recently as April/May 2015, according to the Irish Aviation Authority. It said in a statement that it had conducted an review of the Irish-registered aircraft — which was leased to Kogalymavia — as part of its "Certificate of Airworthiness" renewal process and that "all certifications were satisfactory" at that point.
Photos: Investigators Search Crash Site of Russian Plane
Investigators and rescuers from Egypt, Russia, France, Germany and Airbus continued working at the site of the crash and in Cairo on Monday.
Sources in Egypt's Ministry of Aviation said the contents of the black boxes were still be downloaded on Monday.
Meanwhile, Russia's Emergency Situations Ministry said that 144 bodies had been transferred to the St. Petersburg morgue for identification.
