'90 percent sure' of bomb on jet

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, a member of the investigation team said yesterday.

The Airbus A321 crashed 23 minutes after taking off from the Sharm al-Sheikh tourist resort eight days ago, killing all 224 passengers and crew. Islamic State militants fighting Egyptian security forces in Sinai said they brought it down.

"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 higher degree of certainty about the cause of the crash than the investigation committee has so far declared in public.

Meanwhile, Russia has returned 11,000 of its tourists from Egypt in the last 24 hours, RIA news agency said yesterday, 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 Oct 31, the bell of St Isaac's Cathedral rang 224 times and a service was held in memory of the victims.

Lead investigator Ayman al-Muqaddam announced on Saturday 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.

Asked to explain the remaining 10 percent margin of doubt, the investigator declined to elaborate, but Muqaddam cited other possibilities on Saturday including a fuel explosion, metal fatigue in the plane or lithium batteries overheating.

Islamic State 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.

If the group was responsible, it would have carried out one of the highest profile killings since al Qaeda flew passenger planes into New York's World Trade Center in September 2001.