Homeland Security Secretary Jeh Johnson said Dec. 7 that he would soon announce changes to the national alert system to warn the public about terrorism risks. The changes come amid fresh concerns about terrorism, after last Wednesday's shooting in San Bernardino, Calif. (Reuters)

The Department of Homeland Security is planning to add a new level to its terrorism advisory system to better reflect a “new phase” in the global terrorist threat against the homeland, DHS Secretary Jeh Johnson said Monday.

The new “intermediate” level would be used to alert Americans to a generally heightened risk environment in which the government may not necessarily know where the threat is coming from, Johnson said at a panel discussion in Washington. The new level, which DHS officials said is likely to be announced in the near future, comes amid growing concern about terrorism after the recent attacks in Paris and San Bernardino, Calif.

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The current National Terrorism Advisory System, begun in 2011, contains two levels. Elevated threat means there is a credible terrorist threat against the United States, while imminent threat refers to a more specific impending attack. That system, which replaced the frequently mocked five-color coded system put in place after the Sept. 11, 2001 attacks, has never been used.

Although Johnson ordered a review of the system earlier this year, he described the planned new intermediate level in language that made clear it could help warn against people such as the pair of gunmen who killed 14 people at a public health facility in San Bernardino. Although authorities said the rampage appeared to have been inspired by the Islamic State, the accused shooters — Tashfeen Malik and her husband, Syed Rizwan Farook — had not come to the attention of U.S. officials before the shootings.

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The secretary said the United States is entering “a new phase in the global terrorist threat that involves not just terrorist directed attacks from overseas but also terrorist inspired attacks here on the homeland and in other countries.” In this environment, he said, “having not had a specific credible piece of intelligence reflecting a specific plot is not the end of the story because we’re dealing with the prospect of terrorist inspired attacks by someone who may be below our radar and who could act on a moment’s notice.”

Johnson said he hopes to announce the change soon and that he thinks it “reflects the current environment and current realities.”