Federal regulators as early as today are expected to take a major step toward development of a nationwide emergency alert system that would send text messages to cell phones and other mobile devices wherever a crisis occurs.

Lack of a simple way to deliver vital warnings to residents has hindered emergency response in disasters such as Hurricane Katrina, recent college-campus shootings, and a spate of devastating tornadoes in the Southeast in February.

The Federal Communications Commission is slated to establish technical standards and other requirements that for the first time would make such communication possible, two FCC officials say. The officials requested anonymity because commissioners have not yet voted on the plan