Police are seeking a family of six – including four young children – who have gone missing and are suspected to be travelling to Syria.
Asif Malik, his partner Sara Kiran and their four children – daughter Zoha, seven; son Essa, four; son Zakariya, two; and one-year-old son Yhaya – have not been seen for nearly two weeks.
However, their disappearance – which was described as “entirely out of character” – was not reported to police for nine days, and officers did not issue a public appeal for a further three days.
Officers fear the family, from Slough, Berkshire, might be travelling to a region of Syria controlled by Islamic State of Iraq and the Levant (Isil).
Neighbours said the alarm was raised after the four children failed to attend school.
Their grandmother was also seen looking for them and knocking on other doors in the modern block of flats where they lived, asking if anyone had seen the family.
John Campbell, Thames Valley Police acting deputy chief constable, said: “We are extremely concerned for the safety of this family, especially the four young children.
“We are reaching out to Asif and Sara, in the hope that they hear our messages and we encourage them to make contact with us so we can return them safely to their families who are extremely worried about them.”
The force disclosed the family were last seen on Tuesday April 7.
They were reported missing to police last Thursday, April 16.
Mr Malik, 31, and Miss Kiran, 29, who neighbours said usually wore a full Islamic veil, left home without mentioning any holiday or travel plans to family members, which a force spokesman said was “entirely out of character for this family”.
Police said the family boarded a ferry from Dover to Calais at 00.30am on Wednesday, April 8.
Further enquiries suggest that the family have then travelled south through Europe, possibly by train.
Police also believe the family may have travelled through Budapest, Hungary, on or around Sunday, April 12.
A spokesman said: “Given the online rhetoric from the Islamic State encouraging people to travel to Syria, the direction of travel and concerns voiced by Asif’s family, Thames Valley Police is concerned the family may be seeking to travel to Syria.”
Mr Campbell went on: “We would urge anyone with information about the family’s whereabouts to come forward and speak to police so the family can safely return to the UK.
“We would ask anyone who saw the family as they travelled to Dover, waiting at the port, on the ferry or when they arrived at Calais to contact the police.
“Any piece of information, no matter how small, could help the UK or European authorities to locate the family so that they can be safely returned home to their loved ones.”
He added: “Police have been working with the family of Asif and our colleagues and partners since they were reported missing in an attempt to locate the family and return them to their loved ones.
“We are concerned about anyone who has or is intending to travel to the part of Syria that is controlled by the terrorist group calling themselves Islamic State.
“It is an extremely dangerous place and not a place where young children should be taken.
“The choice of returning home from Syria is often taken away from those under the control of Islamic State, leaving families in the UK devastated and with very few options to secure their loved ones safe return.
“Asif and Sara need to know their family are very concerned and want them to return to the UK.”