NEW : Hospital officials give no immediate confirmation that a demonstrator is killed in Yemen . thousands CNN students were hurt after a protest there . Aden has seen at least the sixth day of clashes between pro- and anti-government crowds .
NEW : Hospital officials give no immediate confirmation that a demonstrator is killed in Aden . Three Sanaa University students were hurt after a protest there . Yemen has seen six days of clashes between pro- and anti-government crowds .