Eight people have been killed in Nigeria after a mob burnt down the house of a Muslim man who intervened when a Christian was beaten over allegations he had blasphemed. 

The incident occured on Monday after a Christian was accused of blasphemy against Islam and the Prophet Muhammad in the northern state of Zamfara. According to witnesses quoted by News Agency of Nigeria (NAN), a large group of Muslim students started to beat their Christian classmate.

But a Muslim passerby intervened and drove the victim to hospital, according to local media reports.

The mob then turned on the Muslim passerby and burnt down his house with eight people trapped inside. The rescuer himself was not among the dead, a police spokesman confirmed.

Nigerian President Muhammadu Buhari condemned the attacks as "barbaric and unacceptable". In a series of tweets he said his prayers were with the families of those affected and promised: "Under my watch we will work to ensure that there is no place for violence in the name of religion, ethnicity, or in any guise whatsoever."

The incident prompted fears of further violence as state governor Alhaji Abdulaziz Yari joined hundreds mourning the deaths.

Yari called an emergency security council and local police have imposed a nightly curfew in an attempt to prevent any escalation.

Nigeria is divided between a Muslim-majority north and a Christian-majority south.

The religious persecution charity Open Doors has ranked Nigeria as one of the most dangerous place in the world to be a Christian. Its annual World Watch Monitor found both Boko Haram and Hausa-Fulani tribesmen "are carrying out religious cleansing, aiming to eradicate Christianity".