A national campaign to stop would-be terrorists travelling to Syria is launching today.
The campaign comes after a dramatic rise in the number of people being arrested after going to the war-torn state, including a pair of men from Sussex.
UK authorities have long expressed fears about aspiring jihadis travelling to Syria for terrorist training, and it is thought that hundreds of Britons have already been there.
Abdullah Deghayes, 18, from Brighton, is believed to have died in Kassab, in Latakia province, earlier this month after leaving the UK in January.
His father Abubaker Deghayes, who learned of his son's death via Facebook, said his two others sons, Jaffar, 16, and 20-year-old Amer have also travelled to Syria and pleaded for them to return.
And Abdul Waheed Majeed, 41, is believed to have driven a lorry to a jail in Aleppo before detonating a bomb in February.
The married father of three, who was born and raised in Crawley, West Sussex, left Britain in 2013, telling his family he was going on a humanitarian mission to Syria.
Today, Scotland Yard said that 40 Syria-related arrests were made in the first three months of this year, up from 25 in the whole of last year.
Senior National Co-ordinator Counter-Terrorism Helen Ball said: "We are increasingly concerned about the numbers of young people who have or are intending to travel to Syria to join the conflict.
“We want to ensure that people, particularly women, who are concerned about their loved ones are given enough information about what they can do to prevent this from happening.
"We want to increase their confidence in the police and partners to encourage them to come forward so that we can intervene and help. This is not about criminalising people it is about preventing tragedies. We want to inform those who wish to genuinely help the Syrian cause how they can do so safely and legally."
Workers from the Prevent counter-terrorism scheme, the Charity Commission and other groups will meet at Scotland Yard today for the launch of the campaign, particularly aimed at women who are concerned about young people planning to travel to Syria.
Other events are also being held across the country, and leaflets highlighting the risks of going to the Middle Eastern state will be handed out at ports. Police have advised those who want to support humanitarian efforts in Syria to donate to charities instead of going there.
Michelle Russell, from the Charity Commission, said: "There is a genuine and desperate need for humanitarian assistance to help people affected by the conflict in Syria. UK charities and their partners are playing an important role in the delivery of humanitarian aid to Syria and its neighbouring countries.
“In part, they have only been able to do this by the generous donations of the public.
"We want everyone to make informed choices about which charities to support and how to support them so that they can feel confident that their contribution really will make a difference to the humanitarian effort."