School districts in Illinois will now be required to conduct safety drills to prepare for a possible shooting under legislation Gov. Pat Quinn signed into law.

The measure, which took effect immediately, will require schools to partner with local law enforcement agencies to develop and conduct a shooting drill at least once a school year. It's up to each school whether students must be present for the exercise and parents can choose to have their children sit out.

The law was developed to better prepare school and law enforcement officials following the December shootings at Sandy Hook Elementary School in Newtown, Connecticut, where a gunman killed 20 children and six staff members. Illinois schools already are required to hold several school and bus evacuation drills and severe weather exercises.

"We must prepared not only for acts of nature, but acts of violence," said sponsoring Sen. Jacqueline Collins, D-Chicago.

Colleges and universities would not be required to conduct the drills, though sponsors of the legislation say that may be the next step.