Egypt's main Islamic university has suspended a controversial preacher and professor over allegations he incited violence and violated the parameters of his job.

Dr Mahmoud Shaaban, who teaches Islamic and Arabic studies at Al-Azhar in Kafr Al-Sheikh, will remain suspended until an investigation into the allegations is complete, according to university president Dr Abdel-Hayye Azab.

The suspension follows a statement by the religious endowments ministry on Sunday that it would fire any imam, employee or worker using government mosques to spread radical thought or incitement.

The ministry also said it would fire any imam or employee in North Sinai proven to have knowledge of underground tunnels or hidden weapons.

It also banned the sale of religious material – audio, video or written – anywhere in the country except with government permission.

A video was published on social media websites last month of a speech by Shaaban in which he referred to ISIS as fellow Muslims who had "made mistakes and whom we are obliged to guide and mentor."

The ministry responded by stating Shaaban is not a licensed imam, and that he will be banned from speaking in mosques.

In February 2013, Shaaban declared a fatwa stating opponents of president Mohamed Morsi must be "deterred by any means, including killing."

A lawsuit was filed against him over the fatwa. He was questioned by the prosecution and released on 5,000 Egyptian pounds bail.

All state institutions have been on maximum alert since a major attack in North Sinai that killed 32 soldiers last month. The president declared a state of emergency in the region, and ordered the evacuation of hundreds of families living near the border with the Gaza Strip.

Since 2011, the Egyptian armed forces have destroyed 1,813 tunnels between North Sinai and Gaza, allegedly to stem the flow of smuggled weapons.