US to roll out new terror alert system

The Obama administration will announce a new terror alert system "in the coming days", Homeland Security Secretary Jeh Johnson said on Monday.

A SWAT team arrives at the scene of a shooting in San Bernardino.

Johnson said the new alert system will better inform the public about threats to the United States, but he did not provide specific details.

This will be the third terror alert system put in place by the Homeland Security Department since the September 11 2001 terrorist attacks.

 The much maligned colour-coded system was replaced in 2011 by the National Threat Advisory System, which has never been used.

Johnson announced the new alert system during a forum with Defence One magazine. He said the National Threat Advisory System hasn't been used because it requires a "specific, credible threat" to the US in order to be activated. The new effort will include an "intermediate" step, he said.

The plan to change the alert system was announced in the wake of the mass shooting in San Bernardino, California, which the FBI has declared a terrorism investigation.

The FBI is investigating the possibility that shooting suspects Syed Farook and Tashfeen Malik were inspired by the Islamic State group to carry out the attacks that killed 14 people attending a holiday luncheon at a social services facility.