A group of around 100 asylum seekers blocked on Monday the main Athens-Thessaloniki highway in protest of living conditions in the Malakasa migrant camp.
Traffic came to a standstill about 45 km (30 miles) north of the Greek capital.
Witnesses say that some of the protesting migrants were bearing sticks and were threatening drivers who tried to pass through.
In the following video a group of protesters are seen chasing away a car.