Paul Pelosi, the husband of US House Speaker Nancy Pelosi, was severely beaten by an assailant weiding a hammer, who broke into their San Francisco home shouting “Where is Nancy?”

Mr Pelosi, 82, suffered blunt force injuries and is being treated by doctors for bruising, severe swelling and other injuries to his head and body.

He is expected to make a full recovery.

Bill Scott, chief of the San Francisco police department, named the suspect as David DePape, 42, in a press conference following the attack.

Charges are to be brought including attempted homicide, assault with a deadly weapon, elder abuse, burglary and other felonies, he said.

The assailant confronted Mr Pelosi shouting for the speaker’s whereabouts, according to another person briefed on the situation.

Nancy Pelosi was not in the residence at the time.

A heart shaped sculpture and a light on are seen inside a window of the home of Paul Pelosi. Photo: AAP

Ms Pelosi’s spokesman Drew Hammill said the assailant was in custody and the motivation for the attack is under investigation.

Investigators work outside the home of Paul Pelosi, Photo: AAP

“The Speaker and her family are grateful to the first responders and medical professionals involved, and request privacy at this time,” Hammill said in a statement.

Ms Pelosi just returned to Washington this week from a security conference in Europe and is due to keynote an advocacy event Saturday evening with Vice President Kamala Harris.

While the circumstances of the attack are unclear, the incident raises additional questions about the safety of members of Congress and their families as threats to lawmakers are at an all-time high almost two years after the violent Capitol insurrection.

Members of Congress have received additional dollars for security at their homes, but some have pushed for more protection as people have showed up at their homes and as members have received an increasing amount of threatening communications.

Often at his wife’s side during formal events in Washington, Paul Pelosi is a wealthy investor who largely remains on the West Coast.

They have five adult children and many grandchildren, and have been married 59 years.

Earlier this year, Paul Pelosi  pleaded guilty to misdemeanour driving under the influence charges related to a May crash in California’s wine country and was sentenced to five days in jail and three years of probation.

Intruder shouted “Where is Nancy, where is Nancy?

The intruder’s words were a chilling echo of the chants during the January 6, 2021, insurrection at the Capitol, when rioters trying to stop Joe Biden’s election searched menacingly for the House speaker.

Threats to lawmakers are at an all-time high almost two years after the Capitol insurrection.

Police tape blocks a street outside the home of Paul Pelosi, Photo: AAP

The attack also comes just 11 days ahead of midterm elections in which crime and public safety have emerged as top concerns among Americans.

In 2021, Capitol Police investigated around 9,600 threats made against members of Congress, and members have been violently attacked in recent years.

Members of Congress have received additional dollars for security at their homes, but some have pushed for more protection as people have showed up at their homes and as members have received an increasing number of threatening communications.

Capitol Police, tasked with protecting congressional leaders, said Nancy Pelosi was with her protective detail in Washington at the time her husband was attacked.

President Joe Biden and lawmakers from both parties reacted to the assault with shock and expressed their well wishes to the Pelosi family.

The Pelosi home in the wealthy Pacific Heights neighbourhood has been the scene of several protests in the past few years.

After Nancy Pelosi was seen on video getting her hair done at a salon while many were shut down during the coronavirus pandemic, stylists protested outside with curling irons.

Members of the Chinese community protested outside recently before Pelosi’s trip to Taiwan. And during debates over the federal stimulus package protesters scrawled anarchy signs in black paint across the garage door, along with “cancel rent,” and “we want everything.”

—with AAP