Washington ? The Amber Alert system used by police to let the public know when a child is missing is being expanded to cell phones.

The wireless industry announced Tuesday that subscribers can receive text messages on their phones when an alert is issued. The service is available in every state and is free to subscribers of most major cellular carriers.

About 200 to 250 Amber Alerts are issued each year. The Internet, radio and television stations broadcast the information, which also is flashed on highway signs on major roadways in the area where the child is believed missing.

Cell phone users who want such information so they can aid in searches can designate up to five ZIP codes and would receive alerts if a child is reported missing in any of them. Subscribers would also be notified of alerts issued for their state or metropolitan area.

Subscribers with phones capable of receiving text messages can register at www.wirelessamberalerts.org or through participating carriers’ Web sites.

Since the alert system began in 1997, more than 200 children have been recovered.

The system is named for 9-year-old Amber Hagerman of Arlington, Texas, who was killed after being kidnapped in 1996.