The suspected Robb Elementary School shooter was not wearing body armor during Tuesday's massacre, multiple law enforcement officials told ABC News.

The alleged gunman was wearing tactical gear, including a vest that could hold ammunition, but there was no armor or fabric that would protect him from gunfire, the sources said.

-ABC News' Matt Gutman, Josh Margolin and Aaron Katersky

President Joe Biden and first lady Jill Biden will be traveling to Texas in the "upcoming days," the president said Wednesday.

The two plan to meet with the victims' families "and let them know that we have a sense, just a sense of their pain. And hopefully bring some little comfort to the community in shock and grief and in trauma," the president said during an address Wednesday afternoon.

The president said he was "sick and tired" of the "carnage" that is happening in the U.S.

"The idea that an 18-year-old can walk into a store and buy weapons of war, designed and marketed to kill, is I think just wrong. Just violates common sense," he said. "Where's the backbone, where's the courage to stand up to a very powerful lobby?"

The accused gunman in Tuesday's deadly school shooting purchased two AR-15-style rifles at Oasis Outback, a federally licensed store located in Uvalde, law enforcement sources told ABC News.

A general manager at Oasis Outback told ABC News that he is working with law enforcement but would not comment on whether the alleged shooter did or did not purchase his guns there.

Oasis Outback is located approximately 3 miles from Robb Elementary School.

According to the Bureau of Alcohol, Tobacco, Firearms and Explosives, the alleged shooter made his gun purchases on two separate days: May 17 and May 20. That means he bought the first AR-15-style rifle one day after he turned 18 and the second four days before the shooting.

Both weapons were purchased at that same store, Steve McCraw, the director of the Texas Department of Public Safety, confirmed during a press conference Wednesday afternoon.

The guns were purchased legally.

-ABC News' Josh Margolin, Aaron Katersky, Laura Romero and Olivia Rubin

The House will move on a bill to create a national red flag law, according to House Majority Leader Steny Hoyer, D-Maryland.

The bill would allow family members or law enforcement officers to "petition for an extreme risk protection order with respect to an individual who poses a risk to themselves or others."

The bill is sponsored by Rep. Lucy McBath, D-Ga., whose 17-year-old son Jordan Davis was fatally shot in 2012.

Hoyer said on Twitter Wednesday that he plans to bring the bill to the floor when the House returns from recess next month.

-ABC News' Lalee Ibssa

When federal agents from Customs and Border Protection and Homeland Security Investigations arrived at Robb Elementary School Tuesday, they immediately encountered a scene of confusion and chaos, according to multiple law enforcement officials briefed on the attack.

Some arrived with heavy equipment, others with whatever they could carry as they ran to the scene on foot.

Initially, these agents, multiple law enforcement sources told ABC News, tried to discern who was doing what, where was shooter who was engaging law enforcement and how were children were being evacuated.

Once the tactical team assembled with enough gear, they became aware of an order not to enter the classroom because they were told the suspect had barricaded himself, the sources told ABC News.

The Texas Department of Public Safety has said the incident commander wrongly believed the shooting had stopped.

Eventually, the special agent-in-charge of Homeland Security Investigations gave the instruction to all federal agents under the umbrella of the Department of Homeland Security that they were free to use their best judgment and to do what they felt was best, the sources said.

The federal agents were unsure whether any children could be saved at that point, but they were interested in evacuating the wounded. Some agents brought children in other classrooms out through windows.

The tactical team went in at 12:50 p.m. CDT and fatally shot the suspect, 77 minutes after the shooting started, officials said.

The suspect was dead at the scene, the sources said. He was found with more than a dozen bullet wounds.