The Department of Homeland Security issued a national terrorism alert warning that violent domestic extremists could attack in the coming weeks, emboldened by the Jan. 6 riot at the U.S. Capitol. DHS, in an alert issued Wednesday, said violent extremists opposed to the government and the presidential transition “could continue to mobilize to incite or commit violence,” though the department said it doesn’t have evidence of a specific plot. The DHS release was part of a public alert called a National Terrorism Advisory System bulletin. The alert is the department’s first in about a year. The last such bulletin from...