The request was made during Friday night prayers at the mosque in Whitechapel, which is one of the largest in Europe.
Salman Farsi, a spokesman for the mosque, said a sister of one of the girls approached the mosque for help and had broken down in tears on the phone.
“I told her that if you need anything from us just let us know and she said that all they need is our prayers and she started crying – that really upset me. I can empathise with them. The community here is quite close and this feels quite close to home,” he said.
Farsi said the girls had been misled and manipulated but said he did not know who or what had persuaded them to flee Britain.
The girls, named as Shamima Begum, 15, Kadiza Sultana, 16, and an unidentified 15-year-old girl, slipped out of their homes in east London last Tuesday and flew from Gatwick airport to Istanbul, Turkey, from where they are thought to be travelling to the Syrian border.
British counter-terrorism police have begun an international hunt to find the girls, all students at Bethnal Green academy in east London.
They were friends with a 15-year-old girl who is believed to have travelled to join Isis last December.
Shamima Begum. Photograph
In the first public appeal of its kind, Scotland Yard counter-terrorism detectives pleaded for information about the whereabouts of the girls and urged them to return home to their “devastated” families.
Mussurut Zia, general secretary of the Muslim Women’s Network UK, said she had grave concerns for the girls and warned it was unlikely they would be able to return home should they join Isis in Syria.
She told BBC Breakfast: “Not for a moment do I believe the girls know what they’re getting into. I don’t think they will be told the true reality. I don’t think they will be actually fighting on the front line ... I think they will be used.
“Jihadi brides is a notion that’s been expressed before; there’s no root in that in religion, but quite possibly that is something they would be used for. I don’t think there is any return for them. I don’t see how they would be able to get back.”
Rushanara Ali, MP for Bethnal Green and Bow, said there was deep concern in the community at the way young people were being radicalised.
“There is shock in what’s just happened. This is a closeknit community,” she told BBC Radio 4’s Today. “One of the things that we have got to do as a country is make sure that schools and teachers and parents who are concerned get advice and help,” she said.
“We need to make sure that we counter these ideologies. This is like grooming, this is child exploitation, and in the worst-case scenario they are potentially being used as weapons of war in those countries.”
The three girls were interviewed in December by detectives about the whereabouts of their friend but were not themselves considered at risk of fleeing Britain. There are now concerns that the girls may be planning to meet up with their friend in Isis-held territory.
Counter Terrorism Command (SO15) Commander Richard Walton said: “We are extremely concerned for the safety of these young girls and would urge anyone with information to come forward and speak to police. Our priority is the safe return of these girls to their families.
“We are reaching out to the girls using the Turkish media and social media in the hope that Shamima, Kadiza and their friend hear our messages, hear our concerns for their safety and have the courage to return now, back to their families who are so worried about them. If we are able to locate these girls whilst they are still in Turkey we have a good possibility of being able to bring them home to their families.”
Walton said it was possible the girls have not yet travelled far from Istanbul, given the snowy weather conditions there, but they are thought to be intending to go toSyria.
Counter-terrorism officers said the three girls left their homes before 8am last Tuesday providing their families with plausible reasons as to why they would be out for the day. One of the girls told her family she would be studying.
Instead they met and travelled to Gatwick airport. They boarded Turkish Airlines flight TK1966, which departed at 12:40pm to Istanbul, Turkey, landing at 6:40pm local time.
Turkish Airlines is facing questions about why it failed to notify police that the girls were travelling alone on a well-worn path to Isis-held territory.
Shamina, who travelled using her sister Aklima’s passport, is described as about 5ft 7in tall. She was wearing black thick-rimmed glasses, a black hijab, a light brown and black leopard-print scarf, dark red jumper, black trousers and jacket, and was carrying a dark blue cylindrical holdall with white straps. She is a British national and speaks English with a London accent. She also speaks Bengali.
Kadiza is described as 5ft 6in tall, of slim build and wearing black-rimmed glasses, a long black jacket with a hood, grey striped scarf, grey jumper, dark red trousers, and carrying a black holdall. She is also a British national who speaks English with a London accent, and also speaks Bengali.
The third missing girl, who is not being named at the request of her family, is described as 5ft 6in tall and of slim build. She was wearing black thick-rimmed glasses, a black headscarf, long dark green jacket with fur-lined hood, light yellow long-sleeved top, black trousers, white trainers and carrying a black Nike holdall. She speaks English and Amharic.