Many independent Muslim schools in England are under threat of closure, according to the Association of Muslim Schools (AMS).
The organisation, which represents almost 100 independent Islamic institutions, said many could not afford to stay open.
Most schools use fees and donations to cover costs and need about £2000 per pupil per year to stay afloat.
But the recession has seen donations fall and parents unable to pay fees.
The threat applies to "almost all" of the 130 Muslim faith schools in England, according to the association.
Among these, 119 are independent and reliant on fees and donations, but 11 are in the state sector so have guaranteed income and are not under threat.
Dr Mohammed Mukadhum, the chairman of AMS, said the schools, attended by thousands of pupils, were hand-to-mouth organisations, operating on a shoestring budget.
Dr Mukadhum said: ''Many of them have been relatively recently established so there has always been some financial struggle.
"But the economic crisis has put them under enormous pressure and they are getting through each day with great difficulty,'' he said.
''The possibility of closing down is a looming reality and the smaller schools are the ones that are most vulnerable,'' he added.
The Iqra Girls' School in Oxford is one of the private independent schools on the brink of closure.
Head teacher Dr Hojjat Ramzy said there was not enough funding to run the school and they could be left with no choice but to close the only Islamic school in Oxford.
''Most of the charitable donations we relied on have dried up and many parents have taken their kids out of the school because they can no longer afford the fees,'' he said.
Some parents have sent their children to schools in Pakistan and Bangladesh instead.
If the school closes, Dr Ramzy fears that more students will be sent abroad because parents do not want their children going to a state school.
He said: ''It will be very sad because they won't get the same quality of education and some may just end up getting married and not completing their studies at all.''
Zainab Rahman, 11, is in year seven at the secondary school.
''I love it here, I get to learn about my religion and I can talk openly about it.
"But if this school shuts down, I won't have anywhere to go," she said.
She said because there were no other Muslim faith schools in Oxford, she would be sent to Pakistan to study and would have to live with relatives there.
Her best friend was sent to Pakistan last month to be educated there, she said, because her parents could not afford the school fees.
''She didn't really have a choice and had to go abroad.
"I've lost touch with her since," Zainab said.
Independent faith schools that are struggling to operate have the option of joining the state sector and becoming a Voluntary Aided School (VAS).
This status means they will receive all their running costs from the government and will not be able to charge fees.
The school will have to follow the National Curriculum, but it may teach Religious Education according to its own affiliated faith.
The government has said it is keen to move more faith schools into the state sector.
A spokesman for the Department for Children, Schools and Families said: "It is always an emotive issue when any independent school faces potential financial difficulties - but there will be no bailouts with taxpayer's money.''
He added: "We have made it far easier for an independent school to join the state sector - as long as it is supported by the local council and community.''
But Dr Mukadhum said many schools did not want to become voluntary aided because then the government would have a more substantial influence in the way they were run.
He said: ''They want to remain independent and so they will have to try to survive by themselves.
"If they are unable to do so it will mean a great loss for all the parents, teachers and students involved.''