(CNN) An Illinois school resource officer is being praised as a hero for intervening when a former student opened fire Wednesday morning at Dixon High School.

US Vice President Mike Pence lauded the "heroic actions" of Dixon Police Officer Mark Dallas, who shot and wounded the gunman.

"Another example of the brave work performed by law enforcement each and every day. Lives were saved thanks to the heroic actions of school resource officer Mark Dallas," Pence said on Twitter.

Suspect Matthew Milby faces three charges of aggravated discharge of a firearm and $2 million bond, Illinois State Police said. More charges may be filed.

The 19-year-old former student opened fire near the school auditorium where students had gathered for graduation ceremony rehearsal, the statement said.

Read More