A family of 12 people from Luton may have traveled to Syria after failing to return from a holiday in Bangladesh.
The group flew to Bangladesh from Heathrow on 10 April and were due to fly back via Istanbul, the first port of call in Turkey for many would-be jihadi recruits heading to Syria, on 14 May.
They were named as Muhammed Abdul Mannan, 75, his wife Minera Khatun, 53, of Spencer Road, Luton, their daughter Rajia Khanom, 21, and sons Mohammed Zayd Hussain, 25, Mohammed Toufique Hussain, 19, Mohammed Abil Kashem Saker, 31, his wife Sheida Khanam, 27, Mohammed Saleh Hussain, 26, and his wife Roshanara Begum, 24, along with three children, aged between one and 11.
In a statement, relatives of the missing said: "We are devastated by the disappearance of these 12 and are very concerned for their safety.
"This is completely out of character and we are very worried of the danger they may now be in.
"Muhammed Abdul Mannan is elderly and both he and Minera Khatun have health issues.
"This just does not make any sense. We can only think they have been tricked into going there, it is no place for elderly or young people.
"We would urge any of them to please make contact with us or the police to let us know they are ok."
Bedfordshire Police said they were investigating the disappearance and urged anyone with information to contact them.
