US, UK Officials Suggest Bomb Exploded Russian Airliner, But Urge Caution

This article was updated to reflect breaking news developments throughout the day.

A bomb may have taken down the Russian airliner that crashed in Egypt’s Sinai region on Saturday, the British government said on Wednesday, suspending all daily British-bound flights departing a southern resort town. The announcement sparked a frenzy in Washington, where U.S. officials told Defense One they back the British suggestion but would not yet confirm the disaster was a deliberate explosion or the Islamic State. 

“While the investigation is still ongoing we cannot say categorically why the Russian jet crashed. As more information has come to light, we have we have become concerned that the plane may well have been brought down by an explosive device,” the British prime minister’s office said in a statement Wednesday.

Later, British Foreign Secretary Philip Hammond, who formerly was the UK defense minister, said that following additional meetings, "We have concluded there was a significant possibility that that crash was caused by an explosive device on board the aircraft."

Later, CNN, Reuters and others reported U.S. officials saying a bomb was "likely." 

The statement out of 10 Downing Street follows a similar warning on Monday from U.S. Director of National Intelligence James Clapper, speaking at the Defense One Summit. Clapper said he wouldn't rule out ISIS involvement, but cautioned at the time that there was no "direct evidence of any terrorist involvement, yet." When asked if ISIS has the ability to shoot down an airliner, Clapper said, “I wouldn’t rule it out.” 

Later Monday, NBC News reported that an American infrared satellite “detected a heat flash at the same time and in the same vicinity over the Sinai where the Russian passenger plane crashed.” The evidence meant, according to U.S. officials, an explosion of "either a fuel tank or a bomb, but that there’s no indication that a surface-to-air missile brought the plane down.”

Perhaps most notably, U.S. intelligence officials now are pointing to a video allegedly taken by ISIS affiliate on the Sinai, which appears to show a plane exploding in air and falling from the sky with a trail of black smoke. If the video is authentic and the group was tracking the plane ahead of time, it's the clearest indication of direct involvement in a plot. Yet, the picture remains muddy. The Islamic State’s Sinai affiliate released an audio message on Wednesday repeating their previous claim to have downed the airliner but the group provided few details. Previous ISIS videos have boasted and shown their abilities to conduct other types of attacks. Egypt’s Prime Minister Abdul Fattah al-Sisi dismissed the claim as “propaganda,” according to the Associated Press.

The plane crashed about 20 minutes after takeoff from Sharm el-Sheikh, killing all 224 passengers on board in the worst civil aviation disaster in Russia’s history.

White House spokesman Josh Earnest refused to comment on the ongoing investigations, but said the U.S. already had standing warnings for civil aviation over the Sinai. He cited a March 2015 advisory from the Federal Aviation Administration about the risks from insurgents—“Man-Portable Air Defense Systems (MANPADS), small arms fire, and indirect fire from mortars and rockets targeting Sinai airports”—to aircraft passing below 26,000 feet in the Sinai airspace, and an earlier warning for flying over 24,000 feet.

“Attacks against aircraft in-flight or weapons fire targeting Sinai airports can occur with little or no warning,” the FAA warned, in March.

As U.S. and foreign officials continue to sift through intelligence and evidence, there has been no indication by the U.S. government of a significant change in military posture or security operations that would suggest they anticipate any additional similar attacks against American targets.