Explosion At Yale

A bomb exploded in an empty classroom at the Yale University law school Wednesday, sending debris flying and students scrambling for safety. No injuries were reported and the damage was minor.

Federal officials said the Connecticut State Police had confirmed the blast was caused by some type of explosive device, possibly a small bomb. But a senior government official said there was no indication it's connected to terrorism, reports CBS News Correspondent Bob Orr.

"We understand there was a device and it went off," Yale spokeswoman Karen Peart said.

The law school also houses a day care and some residences, but it was not clear whether any children or residents were inside at time. The law school is holding final exams through Friday, and officials said tests were given in the building earlier Wednesday.

There were no initial indications that an international terrorist organization set off the bomb, according to two U.S. officials who are familiar with intelligence information. They spoke on the condition of anonymity.

FBI spokesman Ed Cogswell also said that there was no initial communication from any person or group about the explosion. He said FBI agents were at the scene but it was too early to draw conclusions about the blast or those behind it.

Acting Police Chief Francisco Ortiz said the explosion was being treated as a criminal matter, but no possibility had been ruled out. He said damage was limited to the ceiling and a partition in the classroom.

The explosion happened about 5 p.m., sending smoke rising above downtown New Haven.

"I saw a huge fireball come out to the middle of the hallway," said law student Bob Hoo, who was on the ground floor of the law school. "It was there and then it was gone."

Hoo said he did not see anything catch fire or anyone injured before he fled. Law student Alexandra Alperovich, who was sitting in the student lounge, said she saw a wall to the alumni lounge collapse after the blast, but wasn't sure whether anyone was inside.

"Everything started falling and I just ran out right away," she said.

A Yale professor, David J. Gelernter, was seriously injured in 1993 when a Unabomber mail bomb exploded in his campus office. His right hand, arm, ear, lungs and other internal organs were injured.

Theodore Kaczynski was sentenced in 1998 for that attack and others that killed three people and injured 23 from 1978 to 1995.