BROOKLYN - Mayor Michael Bloomberg is standing behind a cell phone ban in public schools following the armed robbery of a truck that stores student cell phones.

According to police, two armed robbers stole 22 phones from a storage truck parked near a Bronx school last week. Opponents of the rule complain that students have to spend money every day to store their phones in trucks outside and say they won't have access to a phone in the case of an emergency.

Bloomberg said he wants to ensure students keep their attention in class.