Please keep the families of these students killed in your thoughts today.
At least 20 people were killed in two shootings when a lone gunman opened fire on the Virginia Tech University campus in Blacksburg on Monday, police said. Police said they believe the shooter also is dead. Amie Steele, editor-in-chief of the campus newspaper, said one of her reporters at one of the dormitories where the shootings took place reported "mass chaos."

12:38PM:
A gunman opened fire in a dorm and classroom at Virginia Tech on Monday, killing 21 people and wounding another 21 before he was killed, police said.

Gunfire erupted in a dorm and classroom at Virginia Tech on Monday, killing at least one person and leaving 21 injured before a suspect was arrested, authorities said.

The university told students to stay inside and away from windows as police swept the campus and worked to establish whether the gunman acted alone.

A hospital spokeswoman said 21 students were treated for gunshot wounds and other injuries.

On the Web site, Tech reported the shootings at opposite sides of the 2,600-acre campus at West Ambler Johnston, a co-ed residence hall that houses 895 people, and said there were "multiple victims" at Norris Hall, an engineering building.

All entrances to the campus were closed and classes canceled through Tuesday.

"There's just a lot of commotion. It's hard to tell exactly what's going on," said student Jason Anthony Smith, 19, who lives in the dorm where shooting took place.

Aimee Kanode, a freshman from Martinsville, said the shooting happened on the 4th floor of West Ambler Johnston dormitory, one floor above her room. Kanode's resident assistant knocked on her door about 8 a.m. to notify students to stay put.

"They had us under lockdown," Kanode said. "They temporarily lifted the lockdown, the gunman shot again."

"We're all locked in our dorms surfing the Internet trying to figure out what's going on," Kanode said.

Madison Van Duyne, a student who was interviewed by telephone on CNN, said, "We are all in lockdown. Most of the students are sitting on the floors away from the windows just trying to be as safe as possible."