Here's what we know about the deadly Russian plane crash that killed all 224 people on board Saturday, Oct. 31. (Monica Akhtar/The Washington Post)

Reversing its earlier position, the Kremlin on Friday announced that it would suspend flights to Egypt in a growing consensus with Western officials that a bomb may have caused a Russian passenger jet to crash over Egypt’s Sinai Peninsula last weekend.

Alexander Bortnikov, President Vladi­mir Putin’s intelligence chief, proposed Friday that flights be grounded as Russian investigators announced that they were seeking traces of explosives in samples of soil, luggage and portions of the plane recovered from the crash site.

The Airbus A321-200 mysteriously disintegrated high over the Egyptian desert last Saturday, killing all 224 people aboard. It is the worst civil aviation disaster in Russian history, and Putin called it “a great tragedy.”

Flights should be halted “until we know the true causes of the incident,” Bortnikov said.

Russia has spent the past week dismissing “speculation” from Western officials, including President Obama and British Prime Minister David Cameron, that the plane may have been downed by a bomb.

But Friday’s decision to table flights, following similar announcements by a half-dozen European countries, seemed to mark a crucial shift in the Kremlin’s position.

“It means that they’re taking information about a possible attack very, very seriously,” said Alexei Makarkin, vice president of the Moscow-based Center for Political Technologies.

Initially, the Islamic State’s affiliate in Egypt asserted responsibility for the crash, which it called revenge for Russia’s intervention in the war in Syria. Russian officials dismissed the claims as opportunism.

If a plot is involved, it could severely alter the public perception of the military campaign in Syria — which some believe could open Russia to increasing risks of retaliatory attacks from groups including the Islamic State, Makarkin said.

“It would be like going from a computer game into a terrifying reality,” he said.

The suspicions were strengthened by French officials, cited anonymously by the magazine Le Point and France 2 television, who were quoted as saying that the flight recorders carry the sound of an apparent explosion that is not believed linked to a malfunction or crew error. The investigation includes experts from France, where Airbus is based.

Although the United States is not directly involved in the investigation, Homeland Security Secretary Jeh Johnson on Friday issued a statement saying that he and Transportation Security Administrator Peter Neffenger, “out of an abundance of caution,” had identified a series of precautionary security enhancements for passengers on U.S.-bound planes from certain airports in the Middle East. They include expanded screening of items on aircraft, airport assessments and assistance to certain foreign airports.

The decision also marks another huge blow to Egypt’s vital tourism industry amid a chaotic mass evacuation of Britons from the southern Sinai and follows assertions by the United States and Britain that a bomb may have torn apart the Airbus A321-200, which was bound for St. Petersburg.

As part of the flight suspensions, Russia also said it would take steps to bring home an estimated 45,000 to 70,000 Russian tourists currently in Egypt, Deputy Prime Minister Arkady Dvor­kovich said.

Egypt is the most popular foreign travel destination for Russians. There are more than 50 flights from Russian cities just to Sharm el-Sheikh each week, and an estimated 3.1 million Russians vacationed in Egypt in 2014.

Before Egypt’s political uprising in 2011, tourism was a pillar of the economy and a main contributor to the country’s foreign currency reserves. But the subsequent turmoil hurt the industry, which saw the number of visitors plummet from a record high of 15 million in 2010 to just 9.9 million last year. The Egyptian government says that 6.6 million tourists arrived in Egypt in the first eight months of 2015 and that about 30 percent were Russian.

Russians began traveling to Egypt in larger numbers after the ruble weakened against the dollar, making more-expensive destinations, such as Western Europe, less accessible. Egypt’s warm climate and affordable accommodations make it a popular tourist destination, industry experts say. The city of Sharm el-Sheikh, which can be reached directly from Russia and a number of other European countries, was seen as an oasis of calm tucked away from the rest of the country’s upheaval. Nearly 570,000 tourists from Britain visited Egypt in the first six months of this year, Egypt says.

Meanwhile, confusion reigned at the airport in Sharm el-Sheikh as Britain struggled to evacuate thousands of its citizens under emergency security rules and tens of flights were canceled.

Egypt’s Civil Aviation Ministry said that just eight of 29 planned Britain-bound flights would depart from the Sharm el-Sheikh airport on Friday. It blamed the snags on limited runway and luggage storage capacities at the airport in the Red Sea resort, even though many airlines canceled service after last week’s crash.

For security reasons, passengers must leave their checked luggage behind. As many as 20,000 Britons are believed to be in and around the resort.

In London, a government statement stressed the “logistical complexities” of flying out thousands of people and predicted that it would take significant time, but it did not give specifics.

At the airport, passengers who had waited in long security lines to board their flights received text messages saying that their returns to Britain had been placed on hold. When the British ambassador to Egypt, John Casson, arrived to calm passengers, he was heckled.

Britain announced that it would suspend all flights in and out of Sharm el-Sheikh on Wednesday over concerns about airport security. Several other European nations followed suit, and carriers including Dubai-based Emirates said it would shift flight paths from Sinai airspace.

Cameron, citing intelligence reports that reportedly included terrorist communications, said Thursday that a bomb “more likely than not” was the cause of the crash.

Putin’s spokesman, Dmitry Peskov, said that Cameron and Putin had not discussed British evidence that last week’s plane crash was an act of terror.

Cameron “did not share that with us,” Peskov told journalists, discussing a phone call on Thursday between the two leaders.

Obama and other senior Western officials had said Thursday that a bomb may have caused the Russian passenger jet to crash in Egypt last weekend, redoubling speculation about a terrorist attack despite heated protests from the governments of both Russia and Egypt.

Witte reported from London. Erin Cunningham and Heba Habib in Cairo, Karla Adam in London and Karen DeYoung in Washington contributed to this report.

Read more:

The rise of Islamic State followers in Sinai

Russian airline official rules out technical error as cause of crash

Today’s coverage from Post correspondents around the world