London, March 16 (IANS): The families of the three London schoolgirls, who have travelled to Syria, have urged them to immediately return home, a media report said on Monday.

Shamima Begum, Amira Abase, both 15, and Kadiza Sultana, 16, left Britain last month for Syria, where it is feared they have joined the Islamic State (IS) terror group, BBC reported.

The families have criticised the Met Police and Bethnal Green Academy, in east London, for not making them aware of another pupil at the school - a friend of the girls - who left for Syria in December.

Sharmeena Begum, 15, left about two months before the three girls.

"With respect to the disappearance of our children, we have been disappointed by the handling of this matter by the school, Met Police and the local authority, all of whom we feel failed to act appropriately and pass on vital information to us or indeed between each other," the families said in a statement.

"Had we been made aware of circumstances sooner, we ourselves could have taken measures to stop the girls from leaving Britain," they said.

Shamima, Amira, and Kadiza were among seven girls spoken to by police at Bethnal Green Academy as potential witnesses after Sharmeena went missing.

According to authorities, all four girls are believed to be in the city of Raqqa - an IS stronghold in Syria.

In the statement, the families said they hoped "lessons are learnt from our experience" and that other families will not have to "bear the same pain we are enduring".

The statement comes in the wake of the news of three teenagers from Britain - comprising two 17-year-old boys from north-west London and a 19-year-old boy - being detained in Turkey on suspicion of trying to enter Syria.

The trio were returned on Saturday night and released on bail pending further enquiries.