Nashville, March 28 : Six victims and the perpetrator of a mass shooting at a school in the US city of Nashville have been identified, authorities said. The three students who were shot and killed on Monday at the Covenant School were all nine years old, according to the Metro Nashville Police Department. Three adult staff members of the school who also died in the mass shooting were named as 61-year-old Cynthia Peak, 60-year-old Katherine Koonce, and 61-year-old Mike Hill, Xinhua news agency reported citing the Department as saying. The shooter, identified as 28-year-old Nashville resident and transgender woman Audrey Hale, was also killed in a shootout with police responding to the incident. Police said Hale, believed to be a former student of the school, was armed with at least two assault-style rifles and a handgun and entered the building through a side door. Nashville Police Department Chief John Drake told reporters they found a manifesto and maps associated with the attack at the Covenant School. "There were maps drawn of the school, in detail of surveillance, entry points," Drake said. "We know and believe that entry was gained through shooting through one of the doors." Police first got calls about the shooting at 10.13 a.m., on Monday morning and responding officers fatally shot Hale after getting to the second level of the building. Investigators are reportedly looking at a possible theory for a motive but did not disclose any details. Nashville Mayor John Cooper said in a statement that the city "joined the dreaded, long list of communities to experience a school shooting". "My heart goes out to the families of the victims. Our entire city stands with you. As facts continue to emerge, I thank our first responders and medical professionals," Cooper added. According to its website, the Covenant School is a private Christian institution that serves about 200 students from preschool through 6th grade. President Joe Biden called the Nashville school shooting "heartbreaking, a family's worst nightmare" during an event at the White House on Monday afternoon. Biden urged Congress to pass an assault weapons ban, saying that we "need to do more to protect our schools". However, it is unlikely that the divided Congress would approve the legislative proposal as Republicans control the House of Representatives this term and have advocated for the Second Amendment right to keep and bear arms. There have been 130 mass shootings in the US so far this year, according to the Gun Violence Archive, which defines a mass shooting as one in which at least four people are shot, excluding the shooter. Meanwhile, 9,894 people, including hundreds of children and teens, have lost their lives to gun violence in the past three months, the website's data showed. Shannon Watts, founder of Moms Demand Action, a grassroots movement that calls for an end to gun violence in the US, tweeted, "gun violence is political in America because gun makers pay our politicians for their inaction". "SCHOOL SHOOTINGS ARE NOT ACTS OF NATURE," Watts wrote. "They are senseless, preventable acts of man enabled by weak gun laws and lawmakers." "This doesn't have to be our new normal. Our children don't have to be sacrificed in exchange for gun industry profits," she continued. On Sunday night, vigils for the six victims were held in the city and mourners gathered in church to pay their respects. /IANS