DUSHANBE, November 9, 2015, Asia-Plus -- A member of the team investigating the crash of a Russian plane in Egypt has said it was likely caused by a bomb.

We will recall that the Airbus A321 crashed 23 minutes after taking off from the Sharm al-Sheikh tourist resort on October 31, killing all 224 passengers and crew.  Islamic State (IS) militants fighting Egyptian security forces in the Sinai said they brought it down.

The Wall Street Journal reported on November 8 that Egyptian authorities have intensely questioned airport workers in Sharm El Sheikh in what employees said was a quest to determine whether insiders facilitated the crash of a Russian plane, as the U.S. echoed the U.K. in asserting that terrorism was the most likely cause.

Reuters on November 8 quoted one of members of the investigation team as saying investigators of the Russian plane crash in Egypt are “90 percent sure” the noise heard in the final second of a cockpit recording was an explosion caused by a bomb.”

"The indications and analysis so far of the sound on the black box indicate it was a bomb," said the Egyptian investigation team member, who asked not to be named due to sensitivities.  “We are 90 percent sure it was a bomb.”

His comments reflect a much greater degree of certainty about the cause of the crash than the investigation committee has so far declared in public.

Lead investigator Ayman al-Muqaddam announced on November 7 that the plane appeared to have broken up in mid-air while it was being flown on auto-pilot, and that a noise had been heard in the last second of the cockpit recording.  But he said it was too soon to draw conclusions about why the plane crashed.

Muqaddam cited other possibilities on November 7 including a fuel explosion, metal fatigue in the plane or lithium batteries overheating, according to Reuters .

Confirmation that militants brought down the airliner could have a devastating impact on Egypt''s lucrative tourist industry, which has suffered from years of political turmoil and was hit last week when Russia, Turkey and several European countries suspended flights to Sharm al-Sheikh and other destinations.

Reuters says IS militants fighting security forces in Egypt''s Sinai Peninsula have said they brought down the aircraft as revenge for Russian air strikes against Islamist fighters in Syria.  They said they would eventually tell the world how they carried out the attack.

Russia has returned 11,000 of its tourists from Egypt in the last 24 hours, Russian news agency RIA Novosti said on November 8, a fraction of the 80,000 Russians who were stranded by the Kremlin''s decision on Friday to halt all flights to Egypt.

In St. Petersburg, where the flight was headed on October 31, the bell of St Isaac''s Cathedral rang 224 times and a service was held in memory of the victims.

Russia has sent specialists to conduct a safety audit of Egypt''s airports and to provide recommendations on additional measures, Arkady Dvorkovich, deputy prime minister, was quoted as saying by Russian media outlets.

Dvorkovich, the head of a government group created on November to deal with suspended flights to Egypt, added a second group went to Egypt on November 8 and a third would be sent later.