Al-Qaeda affiliated terrorists have blown up the tomb of a famous Islamic scholar in southern Syria.

Militants of the al-Nusra front attacked the 13th century tomb of Imam Nawawi in Nawa, a town recently captured by the militants, news agency SANA and London-based Syrian Observatory for Human Rights reported.

Nawawi, born in Nawa in 1233, wrote many books on Islam and was a highly regarded scholar.

The incident occurred as al-Nusra have stepped up their attacks in Syria. Last December, the militants killed some 100 soldiers during a two-day battle in which insurgents took control of two key bases in the Idilib Governorate, south-western Syria.

Al-Nusra, as well as terror group Islamic State (Isis) are Sunni Muslims part of the Salafi movement, whose members seek to restore the practices adopted by Muslims in the past.

They are against shrines and tombs as they see them as sacrilegious.

In July, Isis destroyed the tomb of Jonah, one of the Iraqi cities that fell into the hands of the insurgents in July 2014.

Militant groups have been gaining control of Syrian towns and military bases since the Syrian civil war erupted in 2011, pitting President Bashar al-Assad's supporters against rebels.

The war has caused the death of hundreds of thousands of civilians. According to latest UN's estimates, more than 191,000 people have been killed in the conflict, while millions have fled their homes.

It is estimated that 6.5 million Syrians are internally displaced; of these, half are children.