The first is at San Francisco State University, where the school investigated student who stomped on a Hezbollah flag at an anti-terrorism rally last October.
Violence broke out when one Klan sympathiser, trying to distribute white-supremacist literature, got on to the protesters' side of the barricade and ran into an anti-Klan group burning a Confederate flag.
Last week, hundreds of thousands of protesters took to the streets of Aden, the port city that was once the capital of South Yemen, chanting anti-unification slogans and waving the secessionist flag.