Yeah, unless someone really really big is behind this (or it's aliens), then a US military drone should be able to track and follow one of the unknown drones for a while.
Nah. None of the publicly acknowledged US military drones carries the type of X-band air search radar that would be necessary to reliably track a small aerial target. There is some stuff in development with that capability but it hasn't been fielded yet, and for safety reasons it certainly wouldn't be authorized for flight in controlled civilian airspace or over populated areas.
