Syrian students who faced beatings and worse for opposing President Bashar al-Assad's regime have traded textbooks for guns, taking to the front lines in Aleppo with almost no military training.

Ahmed al-Shawaf was studying Turkish literature at Latakia University until he was kicked off the campus over a demonstration against Assad.

"They saw us before we went to the demonstration," says 21-year-old Shawaf. "The air force intelligence took us."

He has no military training except that which he received from the rebels, but now totes a Kalashnikov assault rifle on the front line in the northern city of Aleppo, large areas of which are scarred by daily bombing and shelling amid piles of uncollected refuse.

"I oppose Assad, I oppose the Assad regime and I oppose him staying in Syria," says Shawaf, sitting with his rifle in front of a mosque damaged by the fighting in Aleppo's Saif al-Dawla neighbourhood.

His goals, he adds, are the fall of the regime, and going back to his studies.

Abu Abdu Sahari, 20, studying electrical engineering at Aleppo University, at first only engaged in non-violent protests against Assad's regime.

But after he was arrested and detained for a month he joined the armed rebellion.

"I did not leave the university, I remain a student, but now I have left (my) studies... to join the revolution," he insists, as shells fired by Assad's forces slam into the front line in the Al-Amriyah neighbourhood.

Abu Abdu Sahari says he joined the rebels because "we began to take many beatings and (regime) armour entered Salaheddin (neighbourhood), and my friend was killed and I was wounded."

He had no military experience before the revolution, but also received training from the rebels.

He hopes to return to his studies some time in the future, but for now he is a fighter in Aleppo, a key battleground between the rebels and Assad's forces.

Omar Shibli, 21, another fighter in Al-Amriyah, was also in the electrical engineering department of Aleppo University.

'I was a hizbi,' a party supporter

But his studies were secondary to his involvement in the uprising that began with protests in March of last year and turned into a civil war when security forces carried out brutal crackdowns on demonstrators and the opposition took up arms.

Shibli says he was once an Assad supporter but turned against the regime because of the injustices he experienced.

"At first, I was a supporter, really. I was a hizbi (Baath party supporter), you know, 'Forever, forever Bashar al-Assad'," he says.

But then he saw "the injustice that happened to us at the university especially, and the injustice that happened to Syria in the revolution," and joined the rebels.

He also had no military experience before the revolution, receiving training only after joining the rebellion. Now he is in a "special group" that operates on various fronts, and has been involved in heavy fighting.

"I took part in the battle of the airport, the battle of Jandul roundabout, the battle of Al-Miyasar, the battle of Sakhur, the battle of Arqub," he says, referring to fierce skirmishes which have shaken Aleppo and its surroundings.

While some Syrian students opposed to Assad have taken up arms, others still put their faith in non-violent demonstrations.

Mohammed al-Hassan, 19, studying chemistry, says he protested at Aleppo University, where he faced heavy-handed responses by the security forces in which some of his friends were killed.

"Really, the regime will not fall except by protests, it will not be toppled by weapons. It will fall by protests and by the power of the voice and the power of the people," Hassan says, during a demonstration in Aleppo's Fardoss neighbourhood.

"God willing, the regime will fall soon."