Security footage appears to show three British girls, believed to be heading for Syria to join Islamic State (IS) militants, waiting at a bus station in Istanbul before travelling to a Turkish town on the Syrian border, media reported Sunday.
Close friends Kadiza Sultana, 16, and 15-year-olds Shamima Begum and Amira Abase, boarded a flight from London to Istanbul on February 17.
British police, who have said the girls are thought to have since entered Syria, and their families have launched urgent appeals for the teens to return home.
The CCTV images show the three girls entering a bus terminal in Istanbul's Bayrampasa district on the European side of the city, which the trio reached by metro from the airport.
They are seen wearing winter coats on top of their niqabs, two of them with hoods pulled up and carrying luggage as they wait, according to footage on the Aksam newspaper's website, which cited security sources.
The footage was recorded in the early hours of February 18, less than 24 hours after the girls left their homes in east London telling their families they were heading out for the day.
At one point they can be seen leaving the waiting lounge of the busy terminal along with other passengers and walking through a snow-covered path into the departure lounge.
The time codes on the images suggest that the girls waited at the terminal for nearly 18 hours before taking a bus to the southeastern Turkish city of Sanliurfa close to the Syrian border.
Aksam said that Turkish police were trying to identify the passengers in the footage helping the girls carry their luggage at the bus station.
Turkey, which has been under fire from its Western allies of failing to do enough to stop jihadists crossing into Syria from its territory, accused Britain of failing to provide information about the girls sooner.
A senior counter-terrorism officer with London's Metropolitan Police, Deputy Assistant Commissioner Helen Ball, said about 60 British women have gone to Syria.
Of these, 22 were reported by their families, including 18 who were aged 20 or younger, she said. The last five reported to have travelled were just 15 and 16.
"This is a growing problem and it's one of real concern," Ball told BBC television, saying that the travel industry must work with police to identify those en route to Syria.
"The more everybody involved in travel understands this problem and can be alerted and be vigilant and look out for people, the better."
But she added: "Some of these women and girls are very carefully prepared for their travel so they don't stand out. They take unusual routes and it is very had to spot them."
An estimated 550 Western women have travelled to join the militants in Iraq and Syria.