A graduate student apparently shot and killed himself Monday morning at a professor's office in the Design College at Arizona State University, authorities said.

The shooting took place about 11:40 a.m. The student was apparently talking with a professor when he pulled out a gun and shot himself, ASU police Cmdr. James Hardina said.

Hardina said that the incident appeared to be isolated and that there was no additional threat to students or faculty.

The suicide took place in the Architecture South Building on the main Tempe campus.

Reid Mosman, a first-year architecture student, said he was on the same floor at the time and heard the noise. He said he thought it sounded like a table or heavy object falling over, so he put his headphones back on and went back to studying.

Several minutes later, authorities came in and ordered everyone out of the building.

More than an hour after the shooting, the building was still locked down as students milled about outside.

The building was closed for the rest of day, and classes were canceled.

ASU officials released a statement encouraging students who may have known the student or those who have been affected by the incident to seek help from the ASU Counseling Centers. Counselors can be reached at 480-965-6146 or at ASU's 24-hour crisis counseling line at 480-921-1006.