The U.S. Marshall's service announced on Friday morning that the Boston Marathon bombing suspect has left the hospital where he has been for the last week, and transfered to a prison hospital on a nearby military base. CNN reports that Dzhokhar Tsarnaev is now at Federal Medical Center Devens, located at Fort Devens, which is an Army Reserve military instillation about 50 miles outside of Boston, in rural Massachusetts.
The fact that he is at military style hospital-prison should not be interpreted as a change in status or an admission that he is now a combatant under military jurisdiction. The hospital actually belongs to the Federal Bureau of Prisons. But the fort location will provide a extra layer of security for a very important prisoner who can't yet (or maybe ever) be put in a regular prison cell. He is also still receiving medical treatment at the Devens hospital, which is used to house prisoners in need of long-term or "specialized" care.