Virginia Tech student Jill Weikert walks with thousands of students to attend a memorial service on the Virginia Tech campus a day after the worst shooting in modern US history

The 32 victims of the massacre at Virginia Tech University come from across the United States and a number of countries across the world.

Details are beginning to emerge in media reports about the identities of a few of the victims, although authorities say it may be days before all their names can be released.

One prominent victim was Liviu Librescu, an engineering and math professor at Virginia Tech.  Librescu was an Israeli citizen who was born in Romania and a Holocaust survivor.  He is internationally-renowned for his research in aeronautical engineering. 

Several of Librescu's students sent e-mails to his wife, Marlena, telling of how he saved their lives by blocking the doorway of the classroom to keep the gunman out.  He blocked the doorway with his body and asked the students to flee out the windows.  He was shot and killed, but his students were saved.

Media reports say another victim was a professor from India, G.V. Loganathan, 51, who was teaching civil and environmental engineering at the university. 

Another victim was an African American student, Ryan Clark, 22, from the southern U.S. state of Georgia.  Reports say Clark had three majors, in biology, psychology and English, and that he had a perfect grade-point average.

Police say they are holding the names of the other victims until identities are confirmed and families have been notified.

Some information for this report was provided by AFP and AP.