Clashes break out on the streets of Cairo, as protesters try to storm the Syrian embassy.
Activists said they wanted to raise the flag of the Syrian rebel army, who've been battling a bloody war with the Syrian government.
Egyptian police fired tear gas to scatter crowds throwing rocks and missiles.
Five people were arrested and there were minor injuries to both sides.
Local media said protesters had marched on the embassy holding pictures of people killed in the 17-month-old conflict.
The embassy has been attacked several times in the past year, as activists demand more international action in Syria.
The latest incident came the night before the Arab League meets in Cairo to discuss the situation.
Around 20,000 people have been killed and scores more injured in Syria's ongoing conflict.