BLACKSBURG, United States, April 16 (Xinhua) -- Hundreds of students gathered in front of the Norris Hall of Virginia Polytechnic Institute and State University (Virginia Tech), in the eastern U.S. state of Virginia, on Monday night to mourn the deaths of more than 30 people who became victims of a shooting rampage in the morning.

    Not far away, two huge, red letters - "VT" - were erected under a tree, and students were seen signing their names on the letters as a way to express their sorrow.

    A total of 33 people, including a gunman, were killed in two shooting incidents at Virginia Tech on Monday morning, the deadliest campus shooting in U.S. history.

    Speaking at a press conference on Monday evening, Virginia Tech President Charles Steger said police received a 911 call at 7:15 a.m. local time, and found two victims in a dormitory room at West Ambler Johnston Residence Hall, in the south of the campus.

    After preliminary investigations, police and school authorities notified all faculty and students of the homicide investigation bye-mail, and asked them to report any suspicious activities. At 9:45 a.m., the police received another 911 call of a shooting at Norris Hall, which contained faculty offices, classrooms and laboratories and was some 800 meters north of the residence hall.

    Police officers found the front doors of the hall had been chained shut from the inside. Within minutes, they forced through the doors and heard gunshots, Steger said.

    The officers followed the succession of gunshots to the second floor, and when they reached the second floor, the gunshots stopped. They found the gunman, who killed himself after shooting many others, he said.

    Thirty-one people including the gunman, were killed at the Norris Hall. Some 15 others were being treated at local hospitals.

    "Our nation is shocked and saddened by the news of the shootings at Virginia Tech today," President George W. Bush said in a statement.

    He said the nation grieved with those who had lost loved ones at Virginia Tech, and pledged that the administration would do everything possible to assist the investigation.

    "Schools should be places of safety and sanctuary and learning. When that sanctuary is violated, the impact is felt in every American classroom and every American community," he said.

    Virginia Tech police chief Wendell Flinchum refused to disclose the identity of the suspected gunman and the victims, and said that police were still trying to determine whether the two shooting incidents were linked.

    The motive behind the shootings remain unknown.

    Flinchum also declined to specify if the two shootings, the first of which was described as being domestic in nature, were carried out by a single gunman.

    Ray Wang, a board member of the Association of Chinese Students and Scholars at Virginia Tech, told Xinhua that he had contacted quite a number of Chinese students but had no word so far that Chinese students were either injured or killed in the incident.

    Founded in 1872, the state university has more than 25,000 full-time students, including 400 to 500 Chinese students, Wang, a doctorate candidate of material science and engineering, told Xinhua.