Domestic terrorism

One of the more significant themes to emerge from the study was that of a perceived desecration of society.

The threat of militia extremist groups increased last year and is expected to continue to be heightened throughout 2021, U.S. intelligence agencies reported.

The bulletin did not cite any specific threat but said that the risk of violence will persist for weeks. It warned that some extremists may be "emboldened" by the Jan. 6 attack on the U.S. Capitol.

A gunman killed 11 worshippers at a synagogue because it supports a Jewish aid group that resettles refugees in the U.S. But volunteers refuse to be deterred. "That is who we are," says one.

Using a rare Oval Office address, the president called last week's deadly San Bernardino shooting "an act of terrorism" and outlined how the U.S. is working to combat the growing threat from ISIS.