The United States Justice Department said on Sunday it will review the response by law enforcement officers to the Texas school shooting that left 19 students and two teachers dead.

The review comes amid public pressure over unclear information about the events that unfolded on Tuesday at Robb Elementary School and how police responded.

In a statement, Justice Department spokesman Anthony Coley said the review would "to provide an independent account of law enforcement actions and response that day, and to identify lessons learned and best practices to help first responders prepare for and respond to active shooter events."

Local media said the shooter entered the school at approximately 11:32 a.m. local time, after shooting his grandmother and crashing his vehicle near the school. He then went on to fire indiscriminately at children and teachers.

The suspect exchanged fire with law enforcement officials and multiple officers were shot. The suspect was eventually fatally shot on the scene.

Reports indicate that more than an hour that elapsed between the time the shooter entered the school and when he was gunned down.

Other reports have noted that students and teachers repeatedly begged 911 operators for help even as a police commander told more than a dozen officers to wait in a school hallway.

(With input from agencies)