Investigator: Noise heard in cockpit recording

However, Ayman el-Muqadem warned it was too early to say what caused the plane to apparently break up in mid-flight.

ReutersEgyptian army soldiers collect belongings of passengers from the crash site of a Russian airliner at the Hassana area in Arish city, north Egypt, November 1, 2015.

“It has elevated concern”, said a USA official, who requested anonymity in order to discuss the issue. Britain and Ireland have suspended flights to Sharm el-Sheikh.

Bahgat was released on Tuesday.

Other countries to have restricted travel to Sharm el-Sheikh include Belgium, the Netherlands and Germany. Egypt’s tourism industry, one of the main sources of foreign income, was yet to fully recover following years of unrest after a January 2011 uprising that toppled former President Hosni Mubarak.

“The indications and analysis so far of the sound on the black box indicate it was a bomb”, a member of the Egyptian team investigating the crash said on Sunday.

The American network NBC, quoting unnamed U.S. officials, said on Friday that communications had been intercepted between IS officials in Syria and people in Sinai about how the jet had been brought down.

Thousands of British holidaymakers remain stranded in Sharm, trying to board the small number of repatriation flights the Egyptian authorities are allowing to take off. Egypt’s Foreign Minister Sameh Shoukry complained on Saturday that Western governments had not sufficiently helped Egypt in its war on terrorism and had not shared relevant intelligence with Cairo regarding the downed Russian airplane that crashed last week in the Sinai, killing 224 people onboard.

Islamic State militants fighting Egyptian security forces in the Sinai said they brought it down.

Meanwhile, in St. Petersburg, mourners filled St. Isaac’s Cathedral for a memorial service for the victims of the plane crash.

The United States are confident that a terrorist bomb is responsable for the desintegration of a Russian plane over Egypt, military officials confirmed for CNN.

Seven officials involved in security at Sharm el-Sheikh airport, several for more than a decade, told the AP of the gaps, speaking on condition of anonymity because they were not authorized to talk to the press.

Officials had said on Saturday that almost 80,000 Russian tourists were still in Egypt, mainly in Sharm el-Sheikh and Hurghada, and that they would be able to return home at their own pace.