WATCH: British teen 'jihadi brides' seen en route to joining ISIS

British police and the girls' families have issued urgent appeals for their daughters to return home after they flew to Istanbul from London on Feb. 17.

By REUTERS
Footage of 3 British schoolgirls thought to be trying to join ISIS
ISTANBUL - Security footage appears to show three British schoolgirls, believed to be on their way to join Islamic State militants, waiting for hours at a bus station in Turkey before travelling to a city near the Syrian border, media reported on Sunday.
British police and the girls' families have issued urgent appeals for their daughters to return home after they flew to Istanbul from London on Feb. 17. Friends Amira Abase, 15, Shamima Begum, 15, and Kadiza Sultana, 16, are thought to have since entered Syria, British police have said.
European governments have called on Turkey to stem the flow of foreign fighters to Syria, and British Prime Minister David Cameron has urged social media firms to do more to deal with online extremism, saying the girls appeared to have been radicalized "in their bedrooms."
The CCTV pictures, dated Feb. 17 and Feb. 18, are from Bayrampasa bus station on the European side of Istanbul, which the girls reached by metro from the airport, Milliyet newspaper said, citing police sources.
They say the girls spent 18 hours at Bayrampasa before boarding a bus to travel to Sanlifurfa, 50 km (30 miles) from the Syrian border region controlled by Islamic State militants.
Turkish police are trying to identify people seen in the footage helping the girls with their luggage at the bus station.
Turkey has complained that Britain was late in notifying it about the girls' arrival.
Security forces estimate that about 600 British Muslims have traveled to the region to join the conflict, some with Islamic State, the extremist Sunni Muslim group that controls a swathe of territory in Syria and Iraq.