Federal prosecutors say the man accused of attacking the husband of US House Speaker Nancy Pelosi with a hammer told police he wanted to hold the speaker hostage and “break her kneecaps”.

David DePape wanted to show other members of Congress there were “consequences to actions”, authorities said on Monday.

In a federal complaint, officials say the 42-year-old was carrying zip ties and tape in a backpack when he broke into the couple’s San Francisco home early on Friday morning before going upstairs where 82-year-old Paul Pelosi was sleeping and demanded to talk to “Nancy”.

When Mr Pelosi told the intruder she was not there, DePape said he would wait — even after being told she would not be home for some days, it said.

“This house and the speaker herself were specifically targets,” San Francisco district attorney Brooke Jenkins said at a Monday evening news conference announcing state charges against DePape, including attempted murder.

“This was politically motivated,” Ms Jenkins said. She implored the public to “watch the words that we say and to turn down the volume of our political rhetoric”.

Investigators believe DePape had been researching in advance to target Pelosi, Ms Jenkins said in an interview with The Associated Press.

“This was not something that he did at the spur of the moment,” she said.

In a statement late on Monday, Speaker Pelosi said her family was “most grateful” for “thousands of messages conveying concern, prayers and warm wishes.” Her husband underwent surgery for a fractured skull and other injuries after the attack and she said he was making “steady progress on what will be a long recovery process”.

The stark narrative laid out by state and federal prosecutors stands in contrast to the mocking jokes and conspiracy theories circulated by far-right figures and even some leading Republicans just a week before midterm elections. A record number of security threats are being reported against politicians and election officials.

At a campaign event on Monday in Arizona, Kari Lake, the Republican candidate for governor, drew hearty laughs as she joked about security at the Pelosi home.

In addition to the state charges, DePape was also charged on Monday in federal court with influencing, impeding or retaliating against a federal official by threatening or injuring a family member. He also faces one count of attempted kidnapping of a United States official because of their official duties.

No attorney has been listed for DePape. He is scheduled to be arraigned on Tuesday on the state charges, and prosecutors will ask for him to be held in jail without bail.

DePape told investigators he wanted to talk to Speaker Pelosi and viewed her as the “leader of the pack of lies told by the Democratic Party”, according to the eight-page complaint.

“If she were to tell DePape the ‘truth,’ he would let her go and if she ’lied’, he was going to break her kneecaps,” the complaint alleges.

“By breaking Nancy’s kneecaps, she would then have to be wheeled into Congress, which would show other members of Congress there were consequences to actions,” the complaint says DePape told investigators.

The federal complaint says DePape said he wanted “to use Nancy to lure” another person, but it provides no details of such a plan.

After DePape confronted Mr Pelosi in his bedroom, Mr Pelosi tried to make it to an elevator in the home to reach a phone, but DePape blocked his way, Ms Jenkins said. In a nightshirt, Mr Pelosi then told the assailant he had to use the restroom, allowing him to get to his mobile phone and call 911, according to authorities.

When police arrived they saw two men struggling over a hammer, and then DePape struck Mr Pelosi at least once before being tackled by officers, Ms Jenkins said.

DePape told investigators he did not leave even though he knew Mr Pelosi had called 911 because “much like the American founding fathers with the British, he was fighting against tyranny without the option of surrender”, the affidavit said.

DePape is a Canadian citizen who legally entered the United States in 2000 but has stayed long after his visa expired, according to a US official who was not authorised to discuss the matter publicly and spoke on condition of anonymity.