University Medical Center is hosting a press conference for the official word on the shooting of Gabrielle Giffords and several of her supporters this morning.

Trauma surgeon Peter Rhee called the situation a catastrophe. He said UMC received 10 patients and one child who is dead. Five are in critical condition and five are in surgery, he said.

The congresswoman is in critical condition. Neurosurgeons have finished operating on her after she was shot through the head one time. Rhee is optimistic about her condition because she was able to follow commands.

Giffords will go into the intensive care unit.

Rhee did not release information about any of the other patients.

Mayor Bob Walkup called it a "grave tragedy" for Tucson, Arizona and the nation. He asked people to pray. He said those who died won't be forgotten.

The Tucson Police Department is supporting the Pima County Sheriff's Department investigation, Walkup said.

Walkup spoke to Giffords' father and told him his family has Tucson's prayers, he said. Giffords' father was overcome with emotion, said Walkup, tearfully.

TPD Chief Roberto Villaseñor said TPD has secured the offices and residences of Giffords and other federal officials as a precaution, although there was no information of a threat.

University of Arizona president Robert Shelton said he sends his thoughts and prayers to the families. He acknowledged the good work of law enforcement and medical professionals.