Zahera Tariq, 33, and her sons Muhammad, 12, Amaar, 11, Aadid, four, and daughter Safiyyah, nine went missing after they disappeared from their London home last week, police say.
They were last seen at their house in Walthamstow, east London, on Tuesday, and are believed to have flown from London to Amsterdam, the Netherlands, on the same day. Police believe all five may be on their way to Syria, according to the Guardian.
Tariq’s husband and the father of her children is thought to be still in the UK.
Police say a relative broke the news of their disappearance on Wednesday to inform them that the family of five might be on their way to Syria.
Detectives later found the family had been captured on CCTV at London City airport prior to their flight to the Netherlands.
Around 700 Britons are estimated to have set out for ISIL-controlled parts of Syria and at least 100 are thought to be women and girls, some travelling with friends and others with children, the report added.