BOSTON - Hospital officials at Massachusetts General Hospital gave an update today on the Boston Marathon victims.

Doctors say 12 patients are currently being treated, and six or seven of them are still listed in critical condition. They say the number of critical patients varies because they are waiting for another update on one of the patients.

Doctors say many of those injured suffered extensive blood loss and leg injuries. They say so far, four patients have had to lose one or both of their legs, but they don't see that number increasing.

Hospital officials say many of the patients treated had pellet-like shrapnel and other nail-like pieces lodged in their legs.