Originally Published: 24 MAY 22 16:00 ET

Updated: 24 MAY 22 18:30 ET

By Jennifer Henderson, Jamiel Lynch and Eric Levenson, CNN

(CNN) -- Two days before the start of summer break, an 18-year-old man opened fire at an elementary school in Uvalde, Texas, on Tuesday, killing 14 students and one teacher, Gov. Greg Abbott said.

Uvalde Consolidated Independent School District police Chief Pete Arredondo said there also were multiple injuries from a "mass casualty incident" at Robb Elementary in Uvalde. The gunman is believed to have acted alone and is dead, he said.

Arredondo declined to provide further details or take questions.

The suspected shooter is from Uvalde, Abbott said. He was identified as Salvador Ramos, according to officials.

"It's believed that he abandoned his vehicle and entered into the Robb Elementary School in Uvalde with a handgun and he may have also had a rifle, but that is not yet confirmed according to my most recent report. He shot and killed, horrifically, incomprehensively, fourteen students and killed a teacher," he said.

The setting of an elementary school called to mind the Sandy Hook shooting in Connecticut in 2012 that left 26 people dead, including 20 children between 6 and 7 years old.

Uvalde Memorial Hospital spokesperson Tom Nordwick earlier said that two people died in the school shooting and that 13 children and a man in his 40s were being treated for injuries.

University Hospital in San Antonio said in a tweet that they received a child and an adult from the school shooting. The adult, a 66-year-old woman, is in critical condition, the hospital said in a tweet.

sA call went out for help for an active shooter situation, according to a law enforcement official.

US Customs and Border Protection, which is the largest law enforcement agency in the area, assisted with the response. A CBP agent was shot in the head. His injuries are non-life-threatening, according to the official.

The governor said two law enforcement officers were hit by bullets, but didn't have serious injuries.

In Uvalde, videos taken by a bystander, Isaias Melendez, show scores of armed officers at the scene while others flee the school.

The FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) are assisting local police with the investigation.

This marks at least the 30th shooting at a K-12 school in 2022. Excluding Tuesday's shooting, so far in 2022 there have been at least 38 shootings in K-12 schools, colleges and universities, resulting in at least 10 deaths and 51 injuries.

The Texas shooting is the deadliest US school shooting since the Marjory Stoneman Douglas High School shooting in Parkland, Florida, in February 2018, when 17 people were killed.

Robb Elementary teaches 2nd through 4th grades and had 535 students in the 2020-21 school year, according to state data. About 90% of students are Hispanic and about 81% are economically disadvantaged, the data shows. Thursday was set to be the last day of school before the summer break.

The school district said it is canceling all school activities following the shooting.

Uvalde County, located about 85 miles west of San Antonio, had a population of about 25,000 as of the 2020 Census.

This is a developing story and will be updated.