SAN FRANCISCO, Oct 29 (AFP) - A man who clubbed U.S. House Speaker Nancy Pelosi's husband over the head with a hammer, shouting, "Where is Nancy?", faced charges of attempted murder and other felonies a day after the violent break-in at the couple's San Francisco home.

Police initially declined to offer a motive for Friday's attack on Paul Pelosi, 82, who according to his wife's office underwent surgery for a skull fracture and injuries to his right arm and hands, though doctors expect a full recovery.

But the assault stoked fears about political violence less than two weeks ahead of midterm elections on Nov. 8 that will decide control of the House of Representatives and Senate, coming amid the most vitriolic and polarized U.S. political climate in decades.

The 82-year-old House speaker herself, a Democrat 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.

She flew to San Francisco to be with her husband.

Police identified the man arrested at the scene by officers who intervened in the attack as David Depape, 42. He, too, was taken to a San Francisco hospital.

Online sheriff's records showed he was booked into custody on suspicion of attempted murder, assault with a deadly weapon, elder abuse, battery, burglary, and several other felonies. Formal charges were expected to be filed by the San Francisco district attorney's office.

San Francisco Police Chief William Scott told a Friday night news briefing that police detectives, assisted by FBI agents, had yet to determine what precipitated the home invasion but said, "We know this was not a random act."

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

The intruder shouted, "Where is Nancy?" before attacking, according to a person briefed on the incident but who spoke to Reuters on condition of anonymity.