Three Coptic Christian teenagers were today sentenced to five years in jail after being charged with insulting Islam, according to AFP.

The three, who are still in high school and aged between 15 and 17, were filmed by their teacher pretending to pray while reciting verses from the Qur'an in January last year. The students are shown in a video laughing, and one appears to pretend to slit the throat of another; apparently mocking ISIS-style beheadings.

The lawyer representing the teenagers, Maher Naguib, told AFP they were "sentenced for contempt of Islam and inciting sectarian strife".

"The judge didn't show any mercy," Naguib added. "He handed down the maximum punishment."

A fourth defendant, aged 15, was sent to a juvenile detention centre for an indefinite period. The teacher, Gad Younan, had previously been sentenced to three years in prison for his role.

When the video was found last year, Naquib previously told the Associated Press that the teenagers were forced to hide in their homes "to avoid insults, beating and harassment".

"This is all because of random and spontaneous action by some youngsters inside a bedroom and for only few seconds," he said.

Hundreds of Muslims attacked Coptic homes and businesses in the village where the students live. Eyewitnesses said more than 15 Christian-owned shops were damaged. Locals also called for the students to be evicted from their village.

Historically, Egypt has been plagued by sectarian violence. Islamic extremists attacked the Coptic Orthodox Church of Alexandria on New Years Eve in 2011, killing 21 people and wounding numerous others.

However, thousands of Muslims then formed human shields outside churches across the country to allow Coptic Christians to safely attend Christmas masses the following week. Christians returned this gesture by joining hands to create a protective barrier for Muslims praying in Cairo during the 2011 Egyptian Revolution.

But despite some displays of solidarity, religious liberty remains an issue.

The United States Commission on International Religious Freedom last year found that the Egyptian government "has not adequately protected religious minorities, particularly Coptic Orthodox Christians and their property from periodic violence".

It condemned "discriminatory and repressive laws and policies that restrict freedom of thought, conscience and religion or belief" and the practice of convicting citizens of blasphemy.

Current legislation in Egypt also dictates that churches cannot be built near schools, villages, railways, residential areas, government offices and canals, among other stipulations.

President Abdel Fattah al-Sisi has pledged to change this, however, and has committed to ending religious intolerance throughout Egypt; calling for a "religious revolution" to tackle extremism. Earlier this year, he pledged to rebuild every single one of the dozens of churches, Christian institutions and homes destroyed during the last two years of anti-Christian violence in Egypt.

"God Has created us different, in religion, manner, colour, language, habit, tradition, and no one can make us the all same," al-Sisi told worshippers during a Coptic Christmas Eve mass at St Mark's Cathedral in Abbassiya.

"We have taken too long to fix and renovate churches that were burned. This year everything will be fixed. Please accept our apologies for what happened. God willing, by next year there won't be a single church or house that is not restored."