The U.S. Attorney's Office said it is not confirming or denying reports that Jared Loughner will plead guilty in last year's shooting rampage outside a Tucson, Arizona, supermarket.
The attack killed six people and wounded 13 others, including then-U.S. Rep. Gabrielle Giffords.
On Saturday night, the Los Angeles Times and the Wall Street Journal reported that Loughner, 23, is now mentally competent to understand the charges against him and that a status hearing on his competency, scheduled for Tuesday morning, will now be a change-of-plea hearing.
The Los Angeles Times attributed the information to "knowledgeable sources," while the Wall Street Journal said its source was an "official familiar with the case."
"I can neither confirm or deny the reports in the L.A. Times and other media about the Loughner case," Bill Solomon, spokesman for the U.S. Attorney's Office in Arizona, told CNN when asked about the reports late Saturday night.
Asked if his office planned to issue a comment Monday, Solomon said, there was "nothing planned at this time."
The attack took place during a January 8, 2011, meet-and-greet event for Giffords. Among those killed was Arizona's chief federal judge, John Roll.
Giffords, who was shot in the head, stepped down from her position in Congress in January 2012 in order to focus on her recovery. Ron Barber, an aide also wounded in the attack, now holds the seat.
Loughner was facing the possibility of a death sentence if convicted. However, a plea deal -- if one is in the works -- may mean that he would admit guilt in exchange for a lengthy prison sentence.
Prosecutors have said that Loughner, who spent time on suicide watch, suffers from schizophrenia. His mental condition has been central to much of the related court proceedings since the mass shooting.
In February, a federal judge ruled Loughner could receive medical treatment for another four months. A psychologist found "measurable progress" in the suspect's condition.
The medical treatment plan for Loughner was aimed at improving his mental state so he will be competent to stand trial.
Loughner was declared incompetent to stand trial in May 2011 after an initial evaluation term at a federal mental hospital in Springfield, Missouri.
In July 2011, bizarre and suicidal actions by Loughner while in custody pushed a federal appeals panel to allow authorities to force the defendant to take anti-psychotic medication.
Prosecutors said then that Loughner had been deteriorating: He displayed screaming and crying fits that lasted hours, harmed himself and made claims that the radio was inserting thoughts into his head.
His attorneys consistently fought court rulings that Loughner continue his treatment at the hospital.
In November, defense attorney Ellis Johnston argued before a different federal judge that the side effects of the psychotropic drugs his client had been receiving during his court-ordered treatment may interfere with Loughner's ability to work with his attorneys.
But Assistant U.S. Attorney Christina Cabanillas said that Loughner "could revert to being a danger to himself" if the medication were halted.
Court documents released a few days after the shooting showed that investigators found a letter from Giffords in a safe at the house where Loughner lived with his parents, thanking him for attending a 2007 event.
"Also recovered in the safe was an envelope with handwriting on the envelope stating 'I planned ahead,' and 'my assassination' and the name 'Giffords,' along with what appears to be Loughner's signature," the affidavit stated.