"It's a massacre," warns opposition spokesman Muhammad Qahtan. "It is a crime by security troops against students engaged in a peaceful sit-in."
Although Washington's persistent silence on Yemen has defied our predictions - making no mention today either - avoiding the crisis tomorrow doesn't seems possible. Should be tragically interesting to watch the U.S. government respond after repeatedly vouching for Yemeni President Ali Abdullah Saleh.
Saleh himself is liable to deny the incident.
[Update: The government has accused protesters of smuggling automatic weapons into the camp and resisting arrest.]