US commandos killed a senior Islamic State group leader in a nighttime raid into Syria, American officials have said, as IS jihadists seized the northern part of Syria's ancient desert city of Palmyra.
Across the border, IS battled Iraqi army reinforcements in the strategic western city of Ramadi, while Turkey said its armed forces had shot down a Syrian helicopter that had violated its airspace.
US President Barack Obama approved the special forces raid on Al-Omar in east Syria on Friday night to capture senior IS leader Abu Sayyaf and his wife Umm Sayyaf, the government said yesterday.
The bold operation, with elite commandos striking at IS's inner circle, was a rare use of "boots on the ground" by the United States, which has fought the jihadists almost entirely from the air.
White House national security spokeswoman Bernadette Meehan said Abu Sayyaf, who played a senior role in IS's lucrative oil operations, "was killed when he engaged US forces".
His wife was being held in military detention in Iraq while a young Yezidi woman, who appears to have been held as a slave by the couple, has been freed.
Al-Omar, one of the largest oilfields in Syria, is in oil-rich Deir Ezzor province, much of which is controlled by IS extremists.
US Secretary of Defence Ash Carter called the operation a "significant blow" to IS, while Adam Schiff, a Democrat on the House intelligence committee, said US attacks "have put increasing pressure on the economics undergirding the terrorist organisation".
Meehan said US forces based out of Iraq conducted the raid "with the full consent" of the Iraqi authorities. They suffered no casualties, officials said, without giving details on the number involved.
Members of the elite Delta special operations unit descended on Sayyaf's compound in Black Hawk helicopters and Osprey tilt-rotor aircraft, a defence official told AFP.
US troops killed "about a dozen" militants in a gun battle before fighting them "at very close quarters... There was hand-to-hand combat," the official said, speaking on condition of anonymity.
Damascus, which Washington did not say it consulted, said the Syrian army had killed IS's "oil minister" in Al-Omar, naming him as Abu al-Taym al-Saudi. A Syrian military source would not confirm if this was another man or Abu Sayyaf.
News of the raid comes the day after Washington authorised sending weapons to the Iraqi military after IS made key territorial gains, seizing a government compound in the strategic Iraqi city of Ramadi.
"IS advanced and took control of most of northern Palmyra, and there are fierce clashes happening now," said Rami Abdel Rahman, director of the Syrian Observatory for Human Rights.
