The aunt of a British teenager who died fighting in Syria has questioned a police appeal to Muslim women to urge their relatives not to fight in the country.

Counter-terrorism police chiefs have launched the unprecedented appeal following a series of deaths of British men who have been killed fighting President Bashar Assad's regime.

Among those who have died on the battlefield was Abdullah Deghayes, 18, from Brighton, who was killed in a gunfight in Kassab in Latakia province earlier this month.

But his aunt Amina Deghayes said that while she welcomed moves to help prevent men travelling to join the conflict, she had not heard anything "helpful or useful" in today's announcement.

She warned that families are already urging their loved ones not to fight in the country, but too often their appeals fall on deaf ears.

She said: "If the steps are to speak to the guys before they leave, I think people already have - they do not need the Government to tell them that.

"In the case of my nephew, he ran away. At what point would we speak to him? I am not being negative. Maybe the actual details of the proposals are more useful than that, but at the moment I haven't heard anything helpful or useful - it would be better than criminalising them, which is the only thing that is going on."

She added: "The problem is I do not even have any possible suggestions, it's very hard to work out what to do.

"Everyone in the family has spoken to my nephews, their mum has been speaking to them, their father has tried to bring them back. What can we do if they think they know better, they think they understand it and it's going to make a difference?

"The problem is they are playing with fire, it's very complicated stuff."

Abdullah's two brothers , Jaffar, 16, and 20-year-old Amer, have also travelled to Syria to fight.

Their father Abubaker has said he is "scared" for his two other sons and pleaded with them to return, but they have refused to go home.

The national campaign to stop would-be terrorists travelling to Syria follows a dramatic rise in the number of people being arrested after going to the war-torn state.

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.

But Ms Deghayes said the threat of prison for those returning from Syria was counter-productive and could lead to British fighters staying there for longer.

She said: "Even if one of them was to consider coming back, they will have to think 'Am I going to prison?'. Fair enough, that may be a consequence of their actions but we have to think of the implications. They are not middle-class thinkers and always thinking of all the possible consequences.

"What can they do? Even if they do change their minds, they are caught between a rock and a hard place.

"If they come back, they may end up in prison. If they do not, they have to stay there."

And she warned that many young men travelled to Syria out of idealism and compassion for those suffering in the conflict - not because they are "evil terrorists".

Home Affairs Select Committee chairman Keith Vaz also questioned the national appeal, warning that i t was unlikely parents would report suspicions about their children to the authorities.

"All the evidence indicates that the families themselves are the last to know," he said.

"They are also most unlikely to tell the police. The police are not the Samaritans, they are the first step in the criminal enforcement process.

"This needs to be addressed at a peer group level, include partnerships with social media and have the full engagement of the communities affected. They hold the key. Young people need to be persuaded that if they go to Syria they may end up dead."

Senior national co-ordinator of counter-terrorism Helen Ball said the appeal was " not about criminalising people" but "about preventing tragedies".

She 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."

Police have advised those who want to support humanitarian efforts in Syria to choose peaceful methods, such as donating to charities, rather than 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."