Story highlights Ahmed H., 40, jailed for 10 years over a riot at a border crossing in Hungary in September 2015

Video footage appears to show Ahmed H., originally from Syria, trying to make peace between crowd and guards

But authorities say he threw rocks at the police, and he was this week convicted of an "act of terror"

London (CNN) Thousands of refugees and migrants, most fleeing violence in the Middle East, mass at the sealed-off border, chanting "Open! Open!" They are desperate to cross into Hungary, but a razor-wire fence, temporary blockade and a line of riot police stand in their way.

As tensions escalate, one voice rises above the fray: A balding, bearded man, wearing a black and white tracksuit top, attempts to negotiate with the officers. "Nobody will make any problem to your country," he tells the officers at Horgos, near the town of Roszke, using a loudspeaker. "Nobody will make any problem to any policeman. You must understand this -- we come here for peace, just to pass."

As he makes his appeal, the man points into the distance, appearing to indicate that the migrants hope only to pass through the Hungary-Serbia border on their way to other countries in the European Union.

Ahmed H. speaking to riot police from behind a blockade on September 16, 2015.

Footage of the incident, recorded by the Hungarian news site Index.hu in September 2015, shows the man stepping back from the temporary barrier before clashes break out. Migrants can be seen hurling objects at the police and forcing open the border gate. In response, riot police fire tear gas and water cannon to disperse the crowd.

The man, identified in court as "Ahmed H.," was sentenced to 10 years in prison Wednesday for taking part in the riot.

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