Pelosi attack suspect pleads not guilty

The man accused of breaking into US House Speaker Nancy Pelosi's San Francisco home and clubbing her husband in the head with a hammer has pleaded not guilty to attempted murder and other charges and was ordered to remain jailed without bond.

David Wayne DePape, 42, showed up for his first court appearance since Friday's attack with his right arm in a sling, a consequence, his court-appointed public defender said, of a dislocated shoulder suffered during the arrest.

The lawyer, Adam Lipson, told reporters afterward that DePape's legal team would review a number of issues that might factor into his client's defence, including his "vulnerability" to "political misinformation" and his mental state.

He pointed to extensive media attention given to the notion, propounded by experts on extremism, that exposure to hate speech trafficked online and amplified by public figures could inspire some mentally unstable individuals to commit acts of political violence.

News coverage of the Pelosi attack has focused on a recent spate of online messages from an individual going by the user name "daviddepape" espousing racist, anti-Semitic and anti-LGBTQ sentiments, while embracing the right-wing conspiracy theory known as QAnon.

The attack, which left Paul Pelosi, 82, hospitalised, has stoked fears about politically motivated violence one week before midterm elections that will decide control of Congress during one of the most vitriolic and polarised campaign seasons in decades.

Appearing in San Francisco Superior Court, DePape was arraigned on state charges of attempted murder, assault with a deadly weapon, burglary, elder abuse, false imprisonment and threatening a public official.

Lipson entered a plea of not guilty to all charges, which prosecutors have said could carry a maximum prison sentence of 13 years to life.

Court documents prosecutors filed on Tuesday shed new light on the suspect's alleged intentions, quoting him as telling police he was on "a suicide mission" and that he named several more prominent politicians and others he planned to target.

DePape spoke little during the hearing before Judge Diane Northway.

Northway ordered DePape to remain in custody without bail for pre-trial proceedings, at least until a formal detention hearing is held. But Lipson told reporters afterward that his client already remained under a federal detention "hold" as well.

DePape is accused in court documents of forcing his way into Pelosi home before dawn on Friday with plans to take the speaker of the US House of Representatives hostage, and to break her kneecaps unless she told him the "truth" under his questioning.

With the Speaker away in Washington at the time, the intruder instead confronted her husband, Paul Pelosi, 82, who managed to furtively call for help.

Police arrived minutes later, just in time to witness the two men struggling with a hammer before the intruder grabbed the tool away and struck Pelosi over the head, according to an FBI affidavit filed in federal court on Monday.

Officers then subdued DePape and took him into custody, authorities said.

The real estate and venture capital executive has since undergone surgery for skull fractures and injuries to his hands and right arm and remained hospitalised on Tuesday.

Nancy Pelosi, 82, said her husband was continuing to make "steady progress on what will be a long recovery process".

Federal prosecutors have charged DePape separately with assault and attempted kidnapping charges punishable by up to 50 years in prison. He has yet to appear in court for the federal case.