The US said it had lost contact with an unarmed Predator drone over Syria, but stopped short of confirming it was taken down by Syrian air defences, as reported by state media.
US officials previously described Syrian airspace as relatively passive, noting that President Bashar al-Assad's government had not taken aim at coalition aircraft flying over its territory.
However, Syria's state news agency SANA said its air defences brought down a US surveillance plane in the coastal province of Latakia.
CCTV footage shows three British teenagers suspected of planning to join Islamic State (IS) militants in Syria, being arrested at Istanbul airport.
The three teens were arrested on suspicion of preparation of terrorist acts after being detained in Turkey and have since been bailed.
The suspects - two 17-year-old boys and one 19-year-old man, all from northwest London - were arrested on Saturday by officers from the Metropolitan Police's Counter Terrorism Command.
The parents of a Scottish woman who left Glasgow to join Islamic State have denied she was involved in recruiting three London schoolgirls.Read the full story ›
An 18-year-old man has been arrested at his home in Birmingham on suspicion of preparing to travel to Syria to join Islamic State, West Midlands Police said.
A new campaign will urge mothers to spot signs their daughters may be considering travel to the war-torn country.Read the full story ›
Three teenagers arrested on suspicion of preparation of terrorist acts after being detained in Turkey have been bailed, Scotland Yard said.
The suspects - two 17-year-old boys and one 19-year-old man, all from northwest London - were arrested by officers from the Metropolitan Police's Counter Terrorism Command.
They have been bailed to return to a central London police station pending further enquiries, police added.
On Friday, CTC officers were made aware that the two 17-year-old boys had gone missing and were believed to be travelling to Syria. Enquiries revealed that they had travelled with the 19 year old.
Three teenagers currently being questioned in London, over claims they 'planned to join Islamic State', are believed to have travelled through Spain before being arrested in Istanbul.
ITV News UK editor Rohit Kachroo reports:
Three teenagers who were flown back to the UK and arrested on suspicion of preparation of terrorist acts after being detained in Turkey returned to London last night, ITV News understands.
A source said the three male suspects had originally been detained at Istanbul Sabiha Gokcen Airport, Istanbul.
Chairman of the Home Affairs Select Committee Keith Vaz said the number of young people attempting to travel to Syria is "clearly" on a "much larger scale" that authorities initially envisaged.
Speaking today as two teenagers from London remain in custody after being detained in Istanbul for allegedly trying to join IS, he said it was vital for parents and authorities to be vigilant.
I welcome the action that has been taken by the Turkish authorities.
We need to prevent people going in the first place and that is why parents need to be vigilant but we also need cooperation from the Turkish authorities in order to stop them from going further.
We need to be vigilant. Clearly this flight of young people to Turkey in order to go to Syria is on a much larger scale than we envisaged.