Jared Loughner pleaded not guilty Monday to charges that he tried to kill Rep. Gabrielle Giffords (D-Ariz.) and two of her aides, the Associated Press reported.

The 22-year-old faces federal charges of trying to assassinate Giffords and attempting to murder two of her aides. He is accused of shooting 19 people Jan. 8 in Tucson, Ariz. Six people died, and Giffords is recovering at a Houston hospital from a gunshot wound to the head.

Prosecutor Wallace Kleindienst said Monday that he expects to know in the next month whether more federal charges will be filed. Loughner is also expected to face state charges.

The hearing was held in a Phoenix courthouse because U.S. District Judge John Roll, one of the six killed, was based in Tucson. Prosecutors have requested to move the federal case back to Tucson, but there was no ruling on the issue Monday.

Loughner’s lawyers could raise his mental competency as a defense, and U.S. District Judge Larry Burns asked Loughner’s defense team Monday whether he can understand the case against him. Attorney Judy Clarke responded, “We are not raising any issues at this time.”