Police shot and killed a 17-year-old-student who opened fire at a Maryland high school on Tuesday. The shooter shot and critically wounded two students at the Great Mills High School in St. Marys County before being confronted by the school resource officer. The shooting, which came amid a renewed national debate over gun violence following a school massacre in Florida last month, occurred just before 8 a.m. (1200 GMT), county Sheriff Timothy Cameron said. A 16-year-old girl and a 14-year-old boy were wounded and taken to hospitals. The girl was in intensive care with life-threatening critical injuries, the sheriff said, while the boy was in good condition. The gunman was identified as Austin Wyatt Rollins, and Cameron said there was "an indication" of a prior relationship between him and the female student, though he said that was still under investigation. Rollins pulled out a Glock semiautomatic handgun around 7:55 a.m. in a hallway and shot the students, the sheriff said. The attack, which lasted less than a minute, ended after the school resource officer, Deputy 1st Class Sheriff Blaine Gaskill, ran inside the building and engaged with Rollins, with both firing a single round almost simultaneously. The officer was not harmed, Cameron sheriff said. Rollins was confirmed deceased at 10:41 a.m. ET after being taken to a hospital. Parkland students and Great Mills students exchanged supportive messages on Twitter following Tuesdays shooting. "We are here for you, students of Great Mills, together we can stop this from ever happening again," Emma Gonzalez, a senior at Stoneman Douglas High School who survived last months rampage, wrote on Twitter. Cameron said investigators would determine whether the shooter died of a wound from the school resource officers gun or in some other way. US President Donald Trump and the National Rifle Association have proposed arming teachers to combat the threat of school shootings, while gun safety advocates have demanded a ban on semiautomatic rifles, among other laws. The Maryland school is in Great Mills, a community about 70 miles south of Washington. "You never think itll be your school and then it is," Mollie Davis, who identified herself as a student at the school, wrote on Twitter. "Great Mills is a wonderful school and somewhere I am proud to go. Why us?" Tuesday’s shooting was the latest in a long string of deadly shootings at US schools and colleges took place a little more than a month after 17 students and educators were shot dead at Marjory Stoneman Douglas High School in Parkland, Florida. That massacre sparked a new student movement against gun violence, including a national school walkout last week that Great Mills students participated in. It occurred just days before a planned Saturday march in Washington calling for new restrictions on guns. "March For Our Lives" is expected to turn out large crowds in US cities. Emma Gonzalez, a Stoneman Douglas student, tweeted her support Tuesday for her peers at Great Mills. "We are Here for you, students of Great Mills," Gonzalez said. "Together we can stop this from ever happening again." Under the banner #ENOUGH, tens of thousands of US high school students walked out of classrooms around the country on March 14 to protest gun violence. Maryland Governor Larry Hogan pledged to provide assistance. "Our prayers are with students, school personnel and first responders," Hogan said in a tweet.