A building collapsed Saturday afternoon in St. Petersburg, Russia, a spokesman for the Russian Emergency Ministry told CNN.

"More than 80 people have been evacuated; there are 24 rescue unit teams working in the area," the spokesman said. He said it was unclear if any people were trapped under the debris.

Three floors of the building collapsed, the second to the fifth, the ministry said.

Rescuers were still working in the building later Saturday.

"So far, we haven't found anyone under the rubble, and no casualties have been reported," the spokesman said.

The spokesman said that the block belongs to the St. Petersburg Research University of Information Technologies, Mechanics and Optics.

The press office for the university told CNN there had been no notification of casualties.

A criminal case has been opened to examine safety violations during construction of the building, state-run news agency Ria Novosti reported, quoting the Russian Emergency Ministry.

The ministry initially said the collapse was at the St. Petersburg University of Low Temperatures and Food Technology.