A massive manhunt is still underway for a gunman who posed as a police officer and killed a US state politician and her husband and wounded a state senator and his wife, attacking them in their homes.
Authorities said the attacks appeared to be politically motivated.
Melissa Hortman, a member of Minnesota's House of Representatives, and her husband were both killed in the early hours of Saturday, local time.
Minnesota state senator John Hoffman and his wife were both shot multiple times and underwent emergency surgery.
State Governor Tim Walz said he was "cautiously optimistic" they would survive.
Both politicians were Democrats.
The gunman, identified as 57-year-old Vance Boelter, had a "manifesto" listing other public officials — believed to be potential targets — in his car, police said.
He remains at large.
The FBI released photos of Mr Boelter wearing a rubber mask in a police-like uniform and offered a reward of up to $50,000 for information leading to his arrest and conviction.
Mr Walz, who was Kamala Harris's vice-presidential running mate in the 2024 election, said: "An unspeakable tragedy has unfolded in Minnesota — my good friend and colleague, Speaker Melissa Hortman and her husband Mark, were shot and killed early this morning in what appears to be a politically motivated assassination."
Local police chief Mark Bruley said a "manifesto" listing other possible targets was found in the gunman's car.
"When we did a search of the vehicle, there was a manifesto that identified many lawmakers and other officials," he said. "We took action on alerting them and providing security where necessary."
US media, citing law enforcement officials, reported the list included other Democratic politicians, and abortion advocates and providers.
Police have asked residents of two suburbs north of Minneapolis to stay inside.
Fears gunman could target rallies
The shootings took place ahead of hundreds of planned rallies across the US to protest the policies and actions of President Donald Trump.
But the local Department of Public Safety recommended protesters not attend any political rallies in Minnesota until the suspect is apprehended, "out of an abundance of caution".
The "No Kings" rallies were expected in almost all major cities in the US except Washington DC, where the largest military parade in America in decades was set to take place, coinciding with Mr Trump's birthday.
A "credible threat" to Texas politicians prompted the evacuation of the state parliament building in Austin, hours before one of the rallies was due to start nearby.
Mr Trump said he had been briefed on the "terrible shooting that took place in Minnesota, which appears to be a targeted attack against state lawmakers". He said the FBI was investigating.
"Such horrific violence will not be tolerated in the United States of America," he said in a statement.
Amy Klobuchar, one of Minnesota's Democratic US senators, condemned the "stunning act of violence" in a post on X, saying her prayers "are with the Hortman and Hoffman families. Both legislators are close friends and devoted to their families and public service".
Fake police officer 'manipulated way' into victims' home
The superintendent of Minnesota's Bureau of Criminal Apprehension, Drew Evans, said police were called to Senator Hoffman's home about 2am Saturday, local time.
He said about 90 minutes later, officers who were "proactively" checking on Ms Hortman's home in a nearby suburb "encountered the individual who immediately fired at them".
Chief Bruley said the gunman had a police badge and equipment, and had driven to Ms Hortman's home in a vehicle equipped with police lights "that looked exactly like an SUV squad car".
He used "the trust of this badge and this uniform to manipulate their way into the home", Chief Bruley said.
Police exchanged fire with the gunman before he retreated back into the home, he said. The man then fled.
Ms Hortman was the House leader of the Democratic-Farmer-Labor (DFL) Party, the state affiliate of the national Democratic Party. She served as House Speaker for six years until earlier this year.
The House DFL caucus said it was shocked and devastated.
"This is an unspeakable act of political violence that should never happen in the United States of America," it said in a statement.
Mr Walz said he had activated Minnesota's Emergency Operations Center and was providing the police in the two suburbs "the full resources" of the state.
