A lockdown at Virginia Polytechnic Institute and State University (Virginia Tech) was lifted Thursday afternoon after hours of search -- to no avail -- of a man carrying a gun.

A Police composite of the person who was suspected of carrying a gun earlier Thursday on the campus of Virginia Tech, formally known as Virginia Polytechnic Institute and State University is seen on their website, August 4, 2011. Police described the suspect as being 6 feet (1.83 meters) tall with light brown hair and wearing a blue and white striped shirt, gray shorts and brown sandals. Authorities shut down the Virginia Tech campus for hours on Thursday after a report of a gunman at the university where 32 people were killed in a mass shooting in 2007. [Xinhua/Reuters Photo]

In an announcement posted on its website, the school, where the worst campus shooting in U.S. history took place in 2007, said the alert was lifted at 2:41 p.m., but the campus would continue to have a large police presence.

"Police have not received nor discovered additional information about a person possibly carrying a weapon beyond that reported this morning," the announcement read. It advised the Virginia Tech community to resume normal campus life, but suggested that people remain vigilant and report suspicious activities to the police.

At about 9 a.m. in the morning, three teenagers attending the summer camp at the university reported seeing a man with a possible handgun, which led to the immediate lockdown and manhunt by the police.

The situation even made its way to the ears of President Barack Obama. White House Spokesman Jay Carney on Thursday said Obama has been briefed about the gun scare, and the White House is monitoring the situation.

"The president has been briefed (on the Virginia Tech situation) , and will be updated," said Carney, noting that the situation there reminded everyone of the tragedy that took place in 2007.

Virginia Tech is the site of the country's most violent school shooting, where 32 were killed and 25 were wounded. The gunman, Seung-Hui Cho, committed suicide afterward.