(Reuters) - An intruder demanding to see U.S. House Speaker Nancy Pelosi broke into her San Francisco home and attacked her husband with a hammer early on Friday, officials said, in an assault that stoked fears about political violence ahead of the Nov. 8 midterm elections.

Paul Pelosi, 82, was taken to a San Francisco hospital where he underwent surgery for a skull fracture and injuries to his right arm and hands, a spokesperson for the House speaker said in a statement. Doctors expect her spouse to make a full recovery, the statement said.

The man arrested at the scene was identified as David Depape, 42, who was also taken to a hospital.

Online sheriff's records showed he was booked into the San Francisco County Jail on suspicion of attempted murder, assault with a deadly weapon, elder abuse, battery, burglary, and other felonies. The booking may have been conducted in absentia, as San Francisco Police Chief William Scott later told reporters Depape was still hospitalized.

The Democratic speaker of the U.S. House of Representatives, who is second in the constitutional line of succession to the U.S. presidency, was in Washington with her protective detail at the time of the assault, according to the U.S. Capitol Police.

Authorities were still investigating a motive for the predawn attack, which was witnessed and interrupted by police officers dispatched to the Pelosi home for an "A-priority wellbeing check," Scott said.

The incident came less than two weeks before midterm elections that will decide control of the House and U.S. Senate, in the midst of a highly polarized political climate.

CNN reported that Paul Pelosi had called emergency-911 and spoke in "code," not saying directly that he was under attack but leading the dispatcher to conclude something was wrong.

Politico, citing a person familiar with the situation, reported separately that Pelosi had told the intruder he needed to use the bathroom, and then furtively called 911 from there, where his cellphone had been charging.

The police chief credited the 911 operator with using her experience and intuition to "figure out that there was more to this incident than what she was being told" by the caller, leading her to dispatch the call at a higher priority than normal. Scott called her decision "life-saving."

'WHERE IS NANCY?'

The intruder shouted "Where is Nancy?" before attacking her husband, a person who was briefed on the incident told Reuters, on condition of anonymity.

A statement from Nancy Pelosi's spokesperson, Drew Hammill, said her husband had been attacked "by an assailant who acted with force, and threatened his life while demanding to see the Speaker."

Little was immediately known about the suspect.

In recent posts on several websites, an internet user named "daviddepape" expressed support for former President Donald Trump and embraced the cult-like conspiracy theory QAnon. The posts include references to "satanic paedophilia," anti-Semitic tropes and criticism of women, transgender people and censorship by tech companies.

Older messages promote quartz crystals and hemp bracelets. Reuters could not confirm that the posts were created by the man arrested on Friday.

The San Francisco Chronicle posted a photo of a man the newspaper identified as Depape dancing at the 2013 wedding of two nudist activists in San Francisco, though he was fully clothed. Depape, then a hemp jewelry maker who lived with the couple in a crowded home in Berkeley, was the best man at the wedding, the newspaper reported.

Scott, the police chief, said the intruder forced entry into the Pelosis' three-story red brick townhouse through a rear door. Aerial photos showed shattered glass on a door at the back of the house, located in the city's affluent Pacific Heights neighborhood.

Scott said police were called to the house at 2:27 a.m. Pacific time (0927 GMT), and from the front door caught their first glimpse of Depape and Paul Pelosi inside struggling over a hammer. As the three officers yelled at both men to drop the tool, Depape yanked the hammer away and was seen striking Pelosi at least once, the chief said.

The officers then tackled, disarmed and arrested Depape and took both men to a hospital, Scott said.