The number of girls and women travelling from the UK to Syria is on the rise according to the latest figures.
Counter terror police fear many are unaware that they will probably never be able to return.
Figures in July showed 43 females were thought to have fled from the UK to war-torn Syria in the previous 12 months.
The latest figures from the UK national counter terrorism policing show 56 women and girls have been reported missing between January 1 2015 and December 31 2015 and are "all feared to have travelled to Syria" according to police.
National Counter Terrorism Police video
The Metropolitan Police's Deputy Assistant Commissioner Helen Ball said: "We are deeply concerned about the numbers of girls, young women and also families who are taking the decision to go to Syria, unaware of the dangers they face when they arrive and the fact that they are unlikely to ever be able to return home to their devastated wider families."
The numbers have been disclosed alongside the release of a short film featuring three female Syrian refugees talking about the realities of life in their home country. The women have also written open letters urging British mothers to take steps to prevent their daughters travelling to the war-zone.
One of the women in the film, Isaaf, says: "Your children are now living in security, are provided with schools, nice life and beautiful future. So why are you taking them to Syria?
"As a mother, and a person who has lived through the war in Syria, your children's future here is better."
Recent high profile cases have included school friends Shamima Begum and Amira Abase, both 15, and Kadiza Sultana, 16, all from Bethnal Green, east London, who left for Syria in February. Some are now thought to be married to Islamic State extremists.
Assistant Chief Constable Angela Williams said: "It is important for everyone do everything they can to help stop people from travelling to Syria and other conflict zones.
"Children have been taken to dangerous places and are at great risk; vulnerable people have been brainwashed into travelling.
"My message to mothers across the region is to please come forward if you have any concerns about your loved ones who may be considering travel to Syria."