Two police officers and a first responder were shot and killed early Sunday in the US state of Minnesota after answering a call about a domestic dispute in a house with multiple children inside, authorities said.The shooter, who has not yet been publicly identified, is dead and the seven children — ranging in age from two to 15 — were all safely rescued, state officers said, declining to provide information on how the shooter died.The slain policemen, both age 27, and a 40-year-old fire department paramedic were shot as they responded to what Minnesota Governor Tim Walz described as “a call of a family in danger” from a home in Burnsville, a city just south of Minneapolis.”This is heartbreaking,” Walz told a press conference Sunday evening, joined by several other public officials.Another officer was shot during the gunfire exchange and has been hospitalized with non-life-threatening injuries.Emergency dispatch received a call at about 1:50 am (0750 GMT) Sunday from inside a home in Burnsville “where a man was reported to be armed and barricaded with family members,” said Drew Evans, superintendent at the Minnesota Bureau of Criminal Apprehension.A standoff ensued as authorities negotiated with the individual, until the man opened fire from inside. At least one of the officers was shot within the home, according to Evans.Multiple guns were recovered from the property but police did not say whether they were pistols or more powerful semi-automatic rifles.”We are in the very beginning stages of this investigation,” Evans said.CBS News footage showed a SWAT armored vehicle on the scene with at least seven bullet holes in its windshield.”Today three members of our team made the ultimate sacrifice for this community. They are heroes,” Burnsville Police Chief Tanya Schwartz told reporters.Shootings are common in the United States, where there are more guns than people and about a third of adults own a firearm.On Wednesday in Missouri, another Midwestern state, one person was killed and 21 others injured when shooting erupted during the Kansas City Chiefs’ Super Bowl victory rally. That same day three police officers were shot during a standoff in the US capital Washington. They are expected to survive, according to media reports.mlm/bfm