Fears family of three sisters and nine children have fled to join Islamic State
Three British sisters are feared to have travelled to war-torn Syria with their children, who are aged as young as three years old.
The news emerged as calls mounted for more to be done to tackle radicalisation of teenagers online after 17-year-old Talha Asmal was reported to have become Britain's youngest ever suicide bomber.
It was also revealed today that Thomas Evans, a Muslim convert from Buckinghamshire, is believed to have died fighting in Kenya fighting for extremist group Al Shabaab.
It is feared 12 members of the Dawood family, from Bradford in West Yorkshire, travelled to Syria where it is understood one of their relatives is fighting for extremists.
According to Balaal Khan, a lawyer acting for the fathers of the missing children, sisters Khadija Dawood, 30, Sugra Dawood, 34, and Zohra Dawood, 33, left Britain on May 28 to go on an Islamic pilgrimage to Saudi Arabia.
They travelled with their nine children and were supposed to return to the UK on June 11.
According to Mr Khan, the missing children are five year-old Muhammad Haseeb, Maryam Siddiqui, seven, Ismaeel Iqbal, three, Mariya Iqbal, five, Zaynab Iqbal, eight, Ibrahim Iqbal, 14, Junaid Ahmed Iqbal, 15, Haafiyah Binte Zubair, eight, and five-year-old Nurah Binte Zubair.
Their family have not heard from them in almost a week, and it is believed that on June 9 they boarded a flight from Madina in Saudi Arabia to Istanbul in Turkey - a commonly used route into Syria.
Mr Khan said: "They are concerned that their children's lives are in danger.
"The concern is for the well-being and safety of the children. The fathers are distraught, they feel helpless and they don't now what to do. They want the children out of harm's way."
He said the sisters and their children have not been in contact for nearly a week, and their Facebook profiles have not been updated.
He said: "It started with a pilgrimage to Saudi Arabia and they were meant to return on June 11, however they have failed to return.
"It has been revealed that on June 9 they have travelled from Madina to Istanbul. Since that day their family have not had any contact with them and their Facebook and Whatsapp profiles have not been updated.
"One of the possibilities is they travelled to Turkey to travel to Syria. The suspicion, and main concern, is that the women have taken their children to Syria."
He said police were notified five or six days ago, but are limited in what they can do because it is out of the jurisdiction.
A West Yorkshire Police spokeswoman confirmed they have received a missing persons report concerning the Dawood family.
The force said that since their disappearance was reported it has been supporting the family, adding that officers have started an investigation to establish their whereabouts and are "working extensively with authorities overseas to try and locate them".
Assistant Chief Constable Russ Foster said: "We are extremely concerned for the safety of the family and would urge anyone with information to come forward and speak to us.
"Our priority is for their safe return; their families are gravely worried about them and want them home. One of our primary concerns is the safety and welfare of the young children."
Talha, 17, is alleged to have fled his home in Dewsbury, West Yorkshire, in March, to join IS - also known as Isis or Isil.
He reportedly detonated a vehicle fitted with explosives while fighting for the group in Iraq.
His family said he had been exploited by extremists on the internet "in a process of deliberate and calculated grooming".
Qari Asim, an imam at the Makkah Mosque in Leeds, said recruitment was mainly taking place online.
"The perpetrators are pretty much acting like paedophiles, they groom these young individuals over time - radicalisation isn't an overnight process," he told the BBC.
"They prey on these vulnerable young people and brainwash them, and religion is a unique passion so they tend to use religion to brainwash these young individuals for their own political aims and gains."
David Cameron's official spokeswoman said the Prime Minister is "clear that the case is deeply concerning".
Asked whether the Prime Minister would seek action from social media companies, the spokeswoman said: "The Prime Minister has spoken several times about the responsibility on a wide range of actors to work together to keep British people safe."
The former reviewer of anti-terrorism legislation, Lord Carlile, called on the Government to work with computer programmers and social media companies to counter extremist propaganda online.
"It's hard to counter, but one does have to use the same tools, the same thought processes, that do radicalise people," said the Liberal Democrat peer.
Sir Bernard Hogan-Howe, the country's most senior police officer, spoke today of the varied nature of the threat faced by the UK.
Speaking ahead of a police counter-terrorism conference, the Metropolitan Police Commissioner said: "Today's terrorist may of course be a hardened member of an organised terrorist 'cell', but may very well also be a lone disaffected youth radicalised by extremist material on his home computer.
"Some of those travelling to Syria are fulfilling a long-standing jihadi ambition. But others who travel to Syria are youngsters fooled by propaganda - out of their depth and running out of time.
"The police must find a way to deal with both."
Unbeknown to them and completely against their will, Talha's family said he travelled to Iraq via Turkey and fell under the spell of Isis handlers who are "too cowardly to do their own dirty work".
Shahid Malik, a former government minister and a family friend of the Asmals, said: "This is a clear indication of just how successful the evil Isis groomers have been in poisoning and brainwashing Talha and kids like him."
Iqbal Bhana, a member of a cross-governmental anti-Muslim hate crime advisory group, said he knew the family of 17-year-old Hassan Munshi, who is believed to have travelled to Syria from Dewsbury with Talha.
He said Hassan's family were "devastated" at the news about Talha and hoped it might make Hassan come home.
He said: "They were hoping against hope and the community has been praying since they went in the hope that they would come back."
Paula Sheriff, Labour MP for Dewsbury, said she was "deeply shocked" and called on the community to unite.
She added: "There is so much good about Dewsbury, yet once again our town has hit the headlines for all the wrong reasons."
Dewsbury was previously embroiled in Islamist extremism when it emerged that Mohammed Sidique Khan, the ringleader of the July 7 attacks in London, lived in the town.
Mr Asim, speaking outside the Makkah Mosque in Leeds, said imams were coming together to "reclaim cyberspace" from the extremist recruiters.
He said: "Isis have been running a very sophisticated social media campaign in order to showcase a romantic, utopian world that they are establishing in Iraq and we all know that's not the case but to young people who are looking for adventure, young people who are looking to play a part and show their creativity, to them it could be very appealing."
He added: "We need to really up our game, reclaim some of the cyberspace and that's what Imams Online are doing, imams from across the country have come together to really reclaim some of that space online by showcasing the true reality of Isis and also really sending a positive message about the true teachings of Islam."
Mr Asim said radicalisation was not isolated to the internet.
He said: "The majority of radicalisation and brainwashing takes place online but I think it would be wrong to say actually it doesn't take place offline because it's pretty much like paedophiles, they will use all sorts of opportunities to their avail to groom people, but what I can say is the radicalisation isn't taking place inside the mosques, it's not taking place in mainstream institutions, it's happening underground or online."
The imam said the Government needed to work with the Muslim community to help find a solution to radicalisation.