At least 19 students and two adults, including a teacher, were killed on Tuesday after a shooting at Robb Elementary School in Uvalde, Texas, according to Gov. Greg Abbott.

The governor said the 18-year-old suspect, Salvador Ramos, is also dead. “It is believed that responding officers killed him,” Abbott said. Ramos allegedly also shot his grandmother before entering the school. Her condition is unknown.

According to Pete Arredondo, chief of police for the Uvalde Consolidated Independent School District, “The investigation is leading to tell us that the suspect did act alone during this heinous crime.”

The shooter allegedly had a handgun and possibly a rifle, Gov. Abbott said. In a statement, Uvalde Medical Hospital said it was treating 15 students in its emergency department following the shooting. San Antonio hospital University Health said it had two patients from the incident — a child and an adult woman, who is in critical condition. The condition of the child is unknown. The Children’s Hospital in San Antonio said it is also treating patients from the shooting.

President Joe Biden addressed the nation on Tuesday night.

He said since he addressed the Sandy Hook Elementary School shooting in 2012, “There have been over 900 incidents of gunfire reported on school grounds. … I am sick and tired of it. We have to act. And don’t tell me we can’t have an impact on this carnage.”

Biden then wondered aloud why shootings are so prevalent in the Unites States.

“These kinds of mass shootings rarely happen anywhere else in the world. Why? They have mental health problems, they have domestic disputes in other countries,” he said.

He issued a missive for lawmakers to “stand up to the gun lobby,” calling for more gun control.

“Why are we willing to live with this carnage? Why do we keep letting this happen? Where in God’s name is our backbone to have the courage to deal with it? It’s time to turn this pain into action,” he added.