Russia struck the Daesh stronghold of Raqqa in Syria on Tuesday with a "significant number" of strikes that may have included long-range bombers and sea-launched cruise missiles, a US defence official said.There was no immediate confirmation from Moscow, but Russian President Vladimir Putin earlier vowed vengeance as Moscow confirmed a bomb brought down a Russian passenger jet over Egypt last month, killing all 224 people aboard.
"We are aware that over the past several hours Russia conducted a significant number of strikes in Raqqa, some of which may have included sea-launched cruise missiles and long-range bombers," said the official, who made the remarks on condition of anonymity.
"While we do not coordinate or collaborate in any way with Russia on its activities in Syria, I can confirm that the Russians did provide us notice prior to conducting these strikes, via the Coalition Combined Air Operations Center in Qatar, in accordance with the safety protocols agreed to in October," the official said.
"These strikes are not affecting coalition operations, and we have not scrapped any missions as a result," the official added.
In a meeting with his security chiefs, Putin pledged to ramp up Moscow's bombing campaign in Syria in response to the attack. But he but stopped short of blaming any one group.
"We will search for them anywhere they might hide. We will find them in any part of the world and punish them," he said.