Egyptian officials probing why a Russian charter jet crashed in the Sinai Peninsula are investigating a "noise" heard in the final second of the flight data recording, they said Saturday.
"A spectrum analysis will be carried out to identity the nature of this noise," Ayman al-Muqaddam, head of the investigation committee, said during a news conference. Such an analysis would help investigators determine the origin of the sound.
The confirmation of the noise comes after Russia's Interfax news agency reported earlier this week that sounds taken from cockpit recordings from the black boxes were "uncharacteristic of a standard flight."
There has been no definitive cause as to what brought down the Metrojet Airbus A321 after it took off from Sharm el-Sheikh Airport on Oct. 31, although Western officials have said it's possible it was downed by a bomb.
The FBI will provide some assistance to the Russian government investigating the crash, a senior FBI official told NBC News Saturday night.
The FBI was asked by the Russians to help, the official said, but the FBI's role was described as "quite modest" and does not include any forensic examination of the wreckage.
Intelligence reports have indicated that a device placed on the airliner caused it to break up in midair, killing all 224 on board, U.S. officials told NBC News.
Muqaddam during the news conference did not confirm that a bomb or an explosion was involved. The black boxes were retrieved the day of the crash, he said.
The crash occurred 23 minutes into the flight, when the auto-pilot was still engaged, and debris was scattered over a wide area extending for 8 miles "which is consistent with an in-flight break-up," he added.
"The committee is considering with great attention all possible scenarios for the cause of the accident and did not reach till the moment any conclusion in this regard," Muqaddam said.
Britain and Russia have suspended flights to and from the Red Sea resort city out of concern for travelers' safety.