The nation’s new terror alert system will use social media sites among other methods to help dispatch clear, targeted warnings to the public, according to a leaked Department of Homeland Security document.

The Associated Press obtained a manuscript summarizing the plan, which replaces the five color-coded terror alert structure created after 9/11.

The 19-page document, labeled “for official use only,” details the chain-of-command when the government fears the nation is vulnerable to terrorism, and even describes how many minutes federal officials should wait before planning conference calls to discuss the threats.

Congressional members would be notified first, then counterterrorism officials in states and cities, governors, mayors and finally the public.

The Homeland Security secretary is at the apex of the system and makes the final call on when to issue an alert and to whom, according to the document.

Terror warnings would be published on Facebook, Twitter and the Homeland Security Web site “when appropriate” and would include expiration dates.

The alerts would state whether threats are “imminent” or “elevated” and are to clearly summarize the potential threat, as well as discuss actions officials have taken to ensure safety and precautionary measures the public should take, according to a memo on the Homeland Security’s Web site.

Alerts would also be catered to impacted audiences. For example, warnings would be issued to travelers if a someone is suspected of carrying explosives into an airport.

According to the Associated Press, some warnings would be marked confidential and withheld from the public if publicizing the information could compromise intelligence investigations.

Federal officials announced their efforts to revamp the anti-terrorism program last January, in hopes of designing a more effective, simplistic system that issues warnings about specific threats. The coded system established after the 9/11 terrorist attacks was often criticized for being too vague.

“Security is a shared responsibility, and we must work together to keep our nation safe from threats,” Homeland Security Secretary Janet Napolitano said in a statement at the onset of developing the new plan. “This new system is built on a clear and simple premise: When a credible threat develops that could impact the public, we will tell you and provide whatever information we can so that you know how to keep yourselves, your families and your communities safe.”

The new system is expected to be activated April 27.