A human rights watchdog has condemned the Islamist terrorist sect Boko Haram for its attack on schools in the flashpoint city of Maiduguri, northeast Nigeria.

"Boko Haram's attacks on schools represent a new and reprehensible development since the group began its campaign of violence in 2009," said Zama Coursen-Neff, deputy children's rights director at US-based Human Rights Watch (HRW).

Members of the group have burned down a total of seven schools over the past week. Buildings were reduced to a pile of smouldering ash, according to Reuters.

At least 5,000 students were off school as a result of the attacks. Boko Haram, whose name translates to "Western education is sin", claimed responsibility, saying the attacks were over the "indiscriminate arrest of students of Koranic schools by security agents".

HRW was angry at the risk to lives and the resulting disruption to education of children.

"Schools may close and children drop out entirely," it warned.

The government's Joint Task Force against terrorism recently said it killed four suspected members of Boko Haram in Maiduguri.

At least 10,000 people have left Nigeria for neighbouring Niger and Chad to escape the military crackdown on the Islamist group.

Suspected members of Boko Haram attacked a popular market in Maiduguri in February, killing up to 30 people. The terrorists reportedly accused fishmongers of leaking secret information to the security forces, which led to the arrest of a prominent sect member.

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