The Al-Mukmin is one among a few pesantrens that have been linked to terrorism, but most pesantrens as well as madrasahs - daily Islamic schools - are moderate Islamic educational establishments and fill the void left by an under-funded and relatively expensive national education system.

Recent Indonesian government estimates suggest that as many as 20 per cent of Indonesia's school-aged children are in Islamic schools, and enrolment rates are increasing by about 7 per cent every year.

The government funds about 10 per cent of the madrasahs' budget and a little more of the pesantrens' costs. The rest is paid by the local communities, and national and international donors. Most madrasahs are owned by private foundations drawn from the local Muslim community.

Government figures show that the 38,500 madrasahs accommodate an estimated 5.7 million students, or 13 per cent of all school-aged students. Just over half are girls, and more than half are children of farmers and labourers.