HOUSTON, Texas (KTRK) -- Houston city leaders have been assuring safety and security in advance of the National Rifle Association convention, which got underway Friday at the George R. Brown Convention Center.
But none of the leaders ignored the potential for high tension in the wake of the Robb Elementary School shooting in Uvalde, Texas, where a gunman unleashed a rampage earlier this week that left 19 children and two teachers dead.
COMPLETE COVERAGE: The Uvalde school shooting
Protest zones, both against the NRA and those countering the opposition, are now activated just across convention doors.
Up to 80,000 people are expected to attend the convention, which Mayor Sylvester Turner said has been on the books for two years. Turner expressed that even though he wishes organizers would consider postponing the event, especially in the wake of the massacre, there is nothing the city can do to force a cancelation that wouldn't expose them to legal liability.
So, with the stage set, national attention shifts to Houston and the convention. Here are the key things to know as the highly-controversial event takes place.
The scene on day 1
Barricades were spotted outside the "GRB" Friday morning ahead of the protests and counter-protests that Houston police are expecting outside.
According to the event schedule, onsite registration that started Thursday afternoon resumed at 8 a.m. The exhibit hall then opened for the business an hour later.
By midday, demonstrators began gathering in the designated protest zone, with chants of "All children matter" being heard.
Just the afternoon before, Houston city hall was the site of a small protest, where one demonstrator questioned the safety of the conference while comparing the situation to a landmark moment during the pandemic.
"If the city can cancel the rodeo for public health, isn't this an issue of public safety?" said Neil Aquino, one of the people who showed up Thursday.
"I feel very strongly that Mayor Turner should cancel the NRA convention," another protester Polly Johnson said.
Gatherings continued into the afternoon, with sign-holding protesters behind barricades facing the street.
Protesters and attendees' safety top of mind, city leaders say
With the NRA convention on, whether protesters or Mayor Turner liked it or not, Houston's police and fire chiefs assured they are prepared to keep protesters and attendees safe.
"We're going to have enough officers to deal with whatever we need to deal with immediately," said Houston Police Chief Troy Finner.
Turner asked the people to remain peaceful and admonished those who plan to attend.
WATCH HERE: PROTESTS GATHERING AS NRA MEETING CONTINUES
"There comes a point in time when people have to realize it's disrespectful to be talking about guns when 19 kids have been killed," Turner said Thursday.
One protest organized by several local groups took place Friday afternoon at Discovery Green. Beto O'Rourke, the Democratic candidate for Texas governor who interrupted a Uvalde press conference the day after the shooting, participated in that one.
SEE MORE: Beto O'Rourke, Parkland survivor challenges NRA in Houston protest
Who is and isn't attending
The guest list for the event is changing.
On Thursday, entertainers Lee Greenwood, Don McLean, and Larry Gatlin, who were set to perform at the meeting, pulled out in light of the massacre.
SEE RELATED STORY: 'American Pie' singer Don McLean pulls out of NRA convention in Houston after Uvalde mass shooting
Two Republican lawmakers, U.S. Rep. Dan Crenshaw and U.S. Sen. John Cornyn, both pulled out a few days ago, before the Uvalde shooting. Crenshaw is in Ukraine and Cornyn, who went to Uvalde in the wake has a scheduling conflict.
ABC13 reached out multiple times to Texas Gov. Greg Abbott's office to find out his plans. We were told Abbott also made the decision not to attend. Instead, Abbott will be in Uvalde for a news conference Friday afternoon.
And just a few hours before convention doors opened, Texas Lt. Gov. Dan Patrick announced that "after prayerful consideration and discussion with NRA officials," he will not make an appearance at the convention.
SEE MORE: Lt. Gov. Dan Patrick drops out of speaking to NRA: 'I would not want to bring additional pain'
Who is at the convention?
Former President Donald Trump's speech got underway just before 5 p.m. He opened by acknowledging the Uvalde tragedy and asked for a moment of silence as he read the names of the 21 victims.
Trump echoed Gov. Abbott's assertion that the gunman's actions were a mental health issue and not an issue with gun access.
The former president then suggested a complete overhaul of school security, including a mandated single point of entry and expanding police department budgets specifically for active shooter training.
"This is not a matter of money. This is a matter of will. The United States has $40 billion to send to Ukraine. We should do whatever it takes to keep our children safe at home," Trump said with the crowd roaring in applause.
Before Trump, U.S. Sen. Ted Cruz spoke to attendees earlier in the Friday afternoon session, opening his address about the evil of the Uvalde school shooting.
"None of us will understand the manifest evil that happened on that day in Uvalde," Cruz said, relating his time in the grief-stricken town this week. "It is an evil that has happened too many damn times."
We don't want a Uvalde to happen, NRA attendees say
Anthony Segura, an NRA trainer in Houston from New Mexico, is attending the conference and said what happened in Uvalde hit him hard as his daughter-in-law is a teacher.
"I can honestly say three nights ago, I didn't sleep all night thinking about it," said Segura. "Everybody blames the gun. Everybody blames the NRA. You know, we are not the bad guy. Our main emphasis is on safety and on training."
"We are just as sorry as anybody else. We don't want to see this happen. All we are trying to say is blaming the gun, blaming the people who own guns, the law-abiding gun owners of this country, we are not the cause of this problem," John Thoesen, another attendee, said.
Check back to this article throughout the day for updates from the conference in downtown Houston.