Russia on Tuesday said that it was coordinating with the French military in sharply ratcheting up attacks on Syrian territory, especially areas held by the Islamic State, as the government for the first time acknowledged that a bomb had destroyed a Russian charter jet that crashed more than two weeks ago in Egypt.
In a related move, President Obama said early Wednesday that he was open to cooperating with Russia in the campaign against the Islamic State, which has asserted responsibility for destroying the charter plane and for the deadly attacks in Paris on Friday, but only if the government of President Vladimir V. Putin begins targeting the militant group.
The timing of the Kremlin’s announcement on Tuesday, after France had already begun striking Islamic State targets and had called for a united front against the group, suggested that Russia was using the moment to help repair frayed relations with the West.
The Kremlin also announced that Mr. Putin and his French counterpart, François Hollande, had spoken by telephone, had agreed to coordinate military attacks in Syria and would meet on Nov. 26 in Moscow.
In a military briefing for Mr. Putin and Defense Minister Sergei Shoigu, which was televised live nationwide, it was announced that Russia had deployed cruise missiles, long-range bombers and other warplanes.
“A massive airstrike is targeting ISIL sites in Syrian territory,” Mr. Shoigu said, using one of the acronyms for the Islamic State. “The number of sorties has been doubled, which makes it possible to deliver powerful pinpoint strikes upon ISIL fighters all throughout the Syrian territory.”
Mr. Putin and his defense chief were shown sitting in a three-story military command center with a map of Syria the size of a movie screen on one wall. In a scene that could have been lifted from a James Bond film, scores of military men, many wearing headsets, were lined up in desks on the main floor and overhead balconies, all facing the screen.
A pariah in Western leadership circles since his invasion of Crimea last year and his support of separatists in eastern Ukraine, Mr. Putin was suddenly front and center at the Group of 20 summit meeting this week in Antalya, Turkey. For Mr. Putin, ending the diplomatic isolation could be an important first step in persuading the West to lift sanctions on his wobbly economy imposed because of the Ukraine dispute.
Speaking after a meeting with President Benigno S. Aquino III of the Philippines, Mr. Obama, who was in Manila for the Asia-Pacific Economic Cooperation summit meeting, said he had had “repeated discussions” with Mr. Putin about the two militaries working more closely together.
“The problem has been in their initial military incursion into Syria, they have been more focused on propping up President Assad,” Mr. Obama said, adding that “If in fact he shifts his focus and the focus of his military, to what is the principle threat, which is ISIL, then that is what we want to see.”
Mr. Obama’s comments are the most direct indication that the United States is prepared to work with Russia to counter the Islamic State, which is also known as ISIS, ISIL or Daesh.
The president suggested that American officials remained skeptical about whether Mr. Putin would shift his focus toward the terrorist group, even in the wake of the Paris attacks.
But he said that the Russians have been “a constructive partner” during diplomatic talks in Vienna last week, where foreign ministers agreed to a path to a cease-fire in Syria and an eventual political transition.
Mr. Obama added that there was a “catch” to that cooperative spirit, saying that “Moscow is still interested in keeping Assad in power.”
He said, however, that “those differences have not prevented us at looking at how could we set up a cease-fire.”
Alexander V. Bortnikov, the head of Russia’s Federal Security Service, said investigators estimated that the bomb that brought down the Metrojet Airbus A321, killing all 224 people aboard, was made of up to 1 kilogram, or 2.2 pounds, of TNT. He added that “foreign made” explosive material had been found in the wreckage.
In remarks to Russia’s Security Council on Monday and broadcast on Tuesday morning, he said that “we can say definitely that this was a terrorist act.”
An “improvised explosive device” detonated soon after the plane took off, Mr. Bortnikov said, adding that “the plane disintegrated in midair, which explains the widely scattered fuselage pieces.”
Egyptian officials have repeatedly asserted that it was premature to conclude that an act of sabotage had destroyed the Russian jetliner, with some saying such an explanation was part of an international conspiracy against their country. But Egypt’s position has become harder to maintain in recent days as the Russian government, one of its closest allies, gave increasing indications that it believed a bomb was the most likely cause. The Russians moved to sever almost all air connections with Egypt.
The plane crashed minutes after departing Sharm el Sheikh, a Red Sea resort now reeling from a loss of the tourism. Russia’s confirmation that the plane was felled by a bomb — presumably smuggled through the Sharm el Sheikh airport — could further weaken Egypt’s vital tourism industry, and undermines government claims of progress in vanquishing militants based in Sinai.
On Tuesday, after hours of silence following the Russian announcement, Egyptian officials seemed to be gingerly walking back their denials. Egypt’s civil aviation minister said the committee investigating the crash had “not arrived at any criminal evidence,” but a statement from the Interior Ministry included the possibility of a “terrorist attack,” while announcing enhanced security measures at airports.
“This is the first time that the Egyptian authorities admit the possibility that whatever happened to the Russian plane was a terrorist attack,” said Mustapha Kamel al-Sayyid, a political science professor at Cairo University and the American University in Cairo. While the change was “not easy” for the Egyptian government, he said, it appeared to reflect an attempt to avoid a rift with the Russians.
The Russians did not acknowledge that the Islamic State had planted the bomb. But the Russian attacks that followed on parts of Syria held by the Islamic State, presented in the live television briefing, left no doubt that the Russians were intent on showing they blamed the group.
Russia fired 34 cruise missiles from the eastern Mediterranean, hitting more than a dozen targets in Aleppo and Idlib, said Gen. Valery Gerasimov, the Russian military’s chief of staff.
Military aircraft, including long-range bombers flying from Russia, flew 127 sorties, hitting 266 targets and destroying 140, the defense minister said. The Russian Air Force deployed in Syria has flown almost 2,300 combat missions since the attacks started 48 days ago, General Gerasimov said.
“We will search for them everywhere, no matter where they are hiding,” Mr. Putin said at a meeting with his security council broadcast on television. “We will find them in any place on the planet and will punish them.”