MOSCOW —The mid-air explosion of a Russian jetliner over the Sinai desert last month that killed all 224 people on board was the result of a terrorist attack, Russia’s chief intelligence officer said Tuesday.
At a meeting with President Vladimir V. Putin, Federal Security Service head Alexander Bortnikov said that traces of explosives found in the plane’s wreckage indicated that an improvised explosive device had been detonated on board.
The statement marked the first time Russian authorities verified the crash was the work of terrorists. Western leaders, including President Obama and British Prime Minister David Cameron, said just days after the Oct. 31 tragedy that a bomb may have been responsible.
The Islamic State has claimed responsibility for the attack, but has provided no additional evidence to support the assertion.
“We can say conclusively that this was a terrorist act,” Bortnikov said on Tuesday, according to an official transcript of the briefing.
Meanwhile, in Egypt, authorities Tuesday detained two employees of Sharm el-Sheikh airport in connection with the downing of the Russian jet, two security officials told the Reuters news agency. The doomed airliner was traveling from the Sinai resort city of Sharm el-Sheikh en route to St. Petersburg, Russia when it exploded in mid-air and crashed into the desert.
“Seventeen people are being held, two of them are suspected of helping whoever planted the bomb on the plane at Sharm el-Sheikh airport,” one of the officials said.
Egypt has still not yet confirmed that a bomb was responsible, saying it wants to wait until all investigations are complete.
In Moscow, Putin, flanked by Bortnikov and other top advisors at a briefing of Russia’s National Anti-Terrorist Committee, said that those behind the attack would be brought to justice.
“We will search for them everywhere, no matter where they are hiding,” he said in remarks that were later televised. “We will find them at any point on the planet and punish them.”
The Russian government offered a $50 million bounty on Tuesday for information about those behind the attack. An affiliate for the Islamic State claimed responsibility for the plane crash in the days following the attack, although the claim could not immediately be verified.
Neither Bortnikov nor Putin indicated the Islamic State by name on Tuesday, although Putin directed Russia’s military to intensify airstrikes in Syria, where the group’s strongholds are located.
U.S. officials have been cautious in blaming the attack on terrorism. Obama said earlier this month that there was “a possibility” that a bomb was on board and “we’re taking that very seriously.” U.S. military officials said an infrared satellite had detected a heat flash, which could have been the result of an explosion, from the plane. But the information was not conclusive, they had added a the time.
Russia launched an intervention in Syria in late September to back the government of Syrian President Bashar al-Assad against its enemies, including the Islamic State, as well as a hodgepodge of Islamist and more moderate rebel forces. Dmitri Peskov, Putin’s press secretary, ruled out a ground operation in Syria when questioned about Putin’s statements Tuesday.
Putin also said that Russia would invoke its right to self-defense under the United Nations charter and called on other countries to aid Russia in its search for the culprits.
“Anyone who tries to supply help to the criminals should know that the consequences for trying to harbor them will lie squarely on their shoulders,” he said.
The Russian government suspended flights to Egypt on Nov. 6 because of concerns of lax security at the airport in the Sinai resort city of Sharm el-Sheikh, where the stricken plane took off from. The jet, on its way to St. Petersburg, Russia, blew up in mid-air shortly after take-off.
Russian tourism officials said this week that more than 70,000 tourists have returned from Egypt, Russia’s most popular tourist destination outside of the former Soviet Union. They have been ferried back to Russia under tight security controls, including a ban on checked luggage, in order to prevent a bomb from being smuggled aboard.
The decision followed similar measures taken by a half-dozen European airlines and a statement by Cameron, the British Prime Minister, that the crash was “more likely than not” caused by a bomb.
Russian officials at the time urged patience until the investigation concluded, but experts said that Tuesday’s news had likely been expected in the Russian government.
“This will not come as too much of a shock to the Russians,” said Dmitry Trenin, the head of the Carnegie Endowment in Moscow.
Trenin said that he did not expect the public to blame Russia’s government for the crash, nor did he think the terrorist attack would sharply change Russia’s foreign policy.
“The Russians have been living in this atmosphere of potential terrorism for a long time, since the 1990s, non-stop virtually,” Trenin said. “It’s not the kind of revelation that the French have just experienced.”
In Moscow, many people expressed condolences for those killed in the attacks, and added that they had believed it was the result of an attack even before Tuesday’s confirmation.
“I was sure it was a terror act from the very beginning,” said Aleksey Kalganov, 37, an engineer, dressed in a dark blue jacket, checked scarf and grey cap. “A plane cannot just fall apart in the air.”
Metrojet, the airline managing the Airbus A321-200, made a similar argument at a press conference shortly after the crash, earning a swift threat from Russian officials to “abstain from premature statements.”
Kalganov said that he had always been afraid of flying because of the possibility of a terrorist attack and preferred traveling by car or train, even over long distances.
“This is their response and I think that there might be more,” he said, adding that he believed this was tied to Russia’s airstrike campaign in Syria. “But nevertheless I support the campaign. They are crazy there, and we should destroy them.”
Others were opposed to the airstrikes.
“This is terrible,” said Elena Lopatina, 44, a manager, when asked about the news of the terrorist attack. “But I am not surprised.”
“No, I do not support the airstrikes, I am against the operation in Syria,” she continued. “I don’t think we can stop now, but I wish we could.”
Daniela Deane contributed to this report from London.