BIRMINGHAM, Ala. -- A man opened fire early Saturday at a hospital in Alabama, wounding a police officer and two employees before being shot and killed by another officer, authorities said.Police were sent to St. Vincent's Hospital at about 4 a.m. to check on a report of an armed man inside the facility. Two officers who arrived separately converged on the suspect on the hospital's fifth floor."When the officer encountered the suspect, there was immediate gunfire from the suspect,'' Birmingham Police Sgt. Johnny Williams said. One police officer and two hospital employees who happened to be in the area were wounded.A second officer shot back, mortally wounding the suspect.Williams said detectives were still trying to determine Saturday why the armed man was in the hospital. Authorities did not immediately release the names of the assailant or the victims.A handful of cardiac patients and several staff members were on the fifth floor, hospital spokeswoman Liz Moore told reporters during a news conference. She said the hospital is secure and stable, and patient care was not interrupted.