NEW YORK (AFP) – Plans were unveiled for a nationwide system that will deliver text-like emergency messages from President Barack Obama and key government agencies to mobile phone users.

The free service, called the Personal Localized Alerting Network or "PLAN," is scheduled to be available in New York by the end of this year and throughout the United States by April 2012.

Urgent messages about terrorist threats, natural disasters, and other emergency events will be sent through participating carriers AT&T, Sprint, T-Mobile and Verizon, to enabled mobile devices.

"PLAN could make a tremendous difference during disasters like the recent tornadoes in Alabama where minutes -- or even seconds -- of extra warning could make the difference between life and death," Julius Genachowski, chairman of the Federal Communications Commission, said in a statement.

Messages will be sent to enabled devices in targeted geographic areas -- rather than to all registered users. Smartphones are currently the only cell phones that have the technological capability of receiving the messages.

The announcement Tuesday was made at the World Trade Center, scene of the September 11 terrorist attacks in 2001.

The alerts will be text-like messages of 90 characters or less.

There will be three types of alerts: issued by the US president; involving imminent threats to safety; and Amber alerts for kidnappings.

Participating carriers may allow subscribers to block all but presidential alerts, according to the FCC announcement.

Genachowski said more carriers will be participating by next year.