South Korean police have turned water cannons on students taking part in a banned pro-unification rally.
The students - who were bombed with liquid yellow dye from a helicopter to identify them for later arrest - were trying to march to the border to meet their North Korean counterparts.
The rally came as both North and South Korea held celebrations marking the 53rd anniversary of the peninsula's liberation from Japanese colonial rule.
Seoul's National University Campus resembled a battle ground on Saturday as demonstrating students clashed with police.
It was the 53rd anniversary of the peninsula's liberation from Japanese colonial rule.
Now - say the students - it's time to bring North and South Korea back together.
This march is part of a three-day festival that culminated in an attempt to march to the North Korean border.
Nevertheless - the police aren't tolerating the rally as the government considered it a stage for anti-Seoul propaganda, and outlawed attendance.
In a bid to mark students for later arrest - yellow dye rained down from a police helicopter.
Undeterred they carried on - chanting the slogan "Let's advance the reunification of the fatherland!"
From behind fences marking the border - police water cannons also buffeted the demonstrators.
At least two students were briefly knocked unconscious and dozens more were hauled off for questioning.
But they weren't deterred.
The students demanded the abolition of Seoul's anti-communist national security law and the removal of 37-thousand U-S troops stationed in South Korea.