New York (CNN) -- A new emergency alert system that sends notifications to cell phones in the event of a disaster or terrorist attack will be implemented in New York and Washington by the end of this year, officials said.
New York Mayor Michael Bloomberg on Tuesday unveiled PLAN, the Personal Localized Alerting Network, which is expected to provide residents with timely information "alerting them to imminent safety threats in their area."
Mobile phone users will receive "geographically targeted, text-like messages," according to a written statement from the Federal Communications Commission.
"Every weekday our population of 8.4 million residents swells to more than 12 million as commuters and tourists come to town," Bloomberg told reporters. "Under the PLAN program, we'll be able to broadcast (emergency) messages to any of them who are within our target area."
Mobile customers will receive three types of alerts containing 90 characters or less, ranging from presidential alerts to child abduction bulletins.
Phone carriers may allow subscribers to block all but presidential alerts, officials said.
A special chip is needed to allow phones to receive the notifications, though many "smart" phones already have the new technology, said FCC spokesman Neil Grace.
"We're a mobile society," said Craig Fugate, Federal Emergency Management Agency Administrator. "How many of us are sitting there listening to a radio or television when these (traditional) alerts come out?"
"This system will send it to your phone."
It will also be able to send messages when cell phone towers experience network congestion, overriding other calls in an effort to deliver the notification.
High mobile phone traffic and downed cell phone towers are considered primary reasons for service disruption in New York in the immediate aftermath of the September 11, 2001, terrorist attacks.
"There are many lessons to be learned from 9/11," said Federal Communications Commission Chairman Julius Genachowski. "One of them is that we were under-utilizing communications technologies in emergencies."
PLAN is expected to be expanded to the rest of the country by April 2012 and was made possible by a 2006 congressional bill called the Warning Alert and Response Network Act.
"It would have been great if we had something like this available as recently as last month for the tornadoes in the south," Genachowski added.
A record number of tornadoes swarmed through much of the Midwest and the South in April, killing hundreds of people and devastating many regions. Meanwhile, flooding in the Mississippi and Ohio river valleys -- largely the byproduct of torrential rains -- has left many local residents in search of higher ground.