The Department of Homeland Security issued warnings to state and local law enforcement agencies this summer regarding the “growing illicit use” of commercial drones, internal documents show. Among the recommended steps was to conduct “exercises to test and prepare response capabilities.”A DHS memo from August, which has not been previously reported, paints US cities as woefully underprepared for the “rising” threat of weaponized drones. The capabilities of unmanned aircraft systems (UAS) are “progressing faster” than available countermeasures offered under “federal prevention frameworks,” the memo says, adding that it’s common for…