国际英语新闻:US Satellite Detects Flash At Time of Russian Plane Disaster

One investigator said the initial analysis showed the plane was not struck from the outside and the pilot did not make a distress call before the plane disappeared from flight controllers' radar.

Cairo and Moscow have played down claims from Egypt's Islamic State branch that it downed the plane.

Aviation and military experts have voiced doubt extremists had missiles capable of hitting a target at an altitude of 9,400 meters.

'No direct evidence'

In Washington, U.S. Director of National Intelligence James Clapper said he knew of "no direct evidence" linking the crash to terrorism. He also said it was "unlikely" that Islamic State had the technical expertise to carry out such an attack, but said "I wouldn't rule it out."

White House spokesman Josh Earnest said U.S. investigators had offered to help probe the disaster. But he did not say whether that offer had been accepted by Moscow.

Russia's Ria Novosti news agency quoted Russian investigator Viktor Sorochenko as saying fragments of the Airbus A-321 were "strewn over a large area." He spoke after visiting the crash site.

Russian President Vladimir Putin said the crash was a tragedy.

"Without any doubt everything should be done so that an objective picture of what happened is created, so that we know what happened," Putin said.

Russia has sent about 100 experts to help Egyptian authorities search for the remains of victims and the aircraft debris.

Several airlines, including Air France, Lufthansa, Dubai-based Emirates and Qatar Airways, have said they will stop flying over the Sinai peninsula for safety reasons. 

Egyptian Civil Aviation chief Hossam Kamal said safety checks before the flight did not turn up any problems, and he said the pilot did not issue a distress call before the plane disappeared.