Somali authorities have arrested seven head teachers who they accuse of meeting al-Shabab militants.

They are said to have discussed changing the curriculum at private schools to favour the Islamist group's ideology.

Each of the principals is responsible for around 1,000 students, ranging in age from seven to 15.

Al-Shabab has been waging a war against Somalia's federal government for the last 10 years.

Mahad Hassan Osman, the information minister for the central Hir-Shabelle region, told the BBC's Somali service that the teachers had been intercepted and arrested near the town of Jowhar.

''We arrested them 15km outside the town.

"They were attempting to change the school's curriculum to suit what the group believes in, which is the implementation of strict Islamic law.''

The minister has said the teachers will be taken to court once an investigation has taken place.

Al-Shabab, which is affiliated to al-Qaeda, has been pushed out of Somalia's main towns but still controls many rural areas.

The militant group launched its own curriculum in April, and produces school textbooks reflecting its Islamist agenda.