U.S. Homeland Security Secretary Jeh Johnson said on Monday that he would soon announce a new alert system to warn the public about terrorism risks.

"We need to get ... to a new system with an intermediate level," Johnson said at a Defense One forum, and he planned to roll one out in the coming days.

The National Terrorism Advisory System is triggered by specific, credible information on a possible threat. The NTAS in 2011 replaced a color-coded alert system, but Johnson said more changes were needed.

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"We need a system that adequately informs the public about what we are seeing," Johnson said.

Johnson said the NTAS system had such a high bar for alerts that the government never used it. Security officials need to do a better job of informing the public about global terrorist threats and providing guidance, he added.

The comments come after 14 people were gunned down on Wednesday in San Bernardino, California, by a couple believed to have been radicalized. President Barack Obama on Sunday night called the shooting an act of terrorism.

Johnson mentioned revising the alert system after five U.S. service members in Chattanooga, Tennessee, were killed in July in a shooting investigated as an act of terrorism.