At least 32 Islamic State group fighters have been killed in apparent US-led coalition raids on Syria as President Bashar al-Assad slammed Britain's decision to participate in air strikes.
The Britain-based Syrian Observatory for Human Rights monitor said at least 32 fighters had been killed in some 15 strikes on the IS stronghold of Raqa province in northern Syria on Sunday.
The monitor's head, Rami Abdel Rahman, said at least 40 jihadists were also wounded in the strikes, which hit IS headquarters and bases to the north, east and southeast of provincial capital Raqa city.
The US-led coalition has been targeting IS in Syria since September last year, expanding a campaign that began with raids in neighbouring Iraq.
Its operations have expanded further in recent days, partly in response to the deadly attacks in Paris claimed by IS.
Britain voted on Wednesday to join the coalition's strikes in Syria, after a heated debate in the country's parliament and with the staunch backing of Prime Minister David Cameron.
And German lawmakers on Friday approved plans to join the military action against the group in Syria.
In an interview published Sunday in Britain's The Sunday Times newspaper, Assad slammed London's decision to begin strikes in Syria as "illegal" and said its actions would cause "terrorism" to spread.
"It will be harmful and illegal and it will support terrorism as happened after the coalition started its operation a year or so (ago)," he told the newspaper.
Terror, he said, was like a cancer which needed to be tackled with a "comprehensive" strategy that would involve working with troops on the ground.
"You cannot cut out part of the cancer. You have to extract it. This kind of operation is like cutting out part of the cancer. That will make it spread in the body faster."