NEW : The number of casualties is unclear . NEW : A new report says the death toll could be as high as 10,000. NEW The attack happened while the university is on a break , so most of the students are not on campus , Tanko said . : The gunmen opened fire and threw four or five bombs , a journalist says . A university professor says he heard gunfire and multiple explosions .
NEW : The number of casualties is unclear . NEW : A new report says the death toll could be as high as 10,000. NEW : The gunmen opened fire and threw four or five bombs , a journalist says . A university professor says he heard gunfire and multiple explosions .