A Florida judge has ordered that the suspect in a deadly shooting rampage at a high school will be held without bond on 17 counts of murder.

Nineteen-year-old Nikolas Cruz was wearing an orange jumpsuit with his hands cuffed at his waist during the Thursday afternoon hearing. His attorney did not contest the order and had her arm around Cruz during the brief court appearance.

Cruz is accused of opening fire Wednesday afternoon at Marjory Stoneman Douglas High School in Parkland, killing 17 people. 

Broward Sheriff Scott Israel said Cruz was a former student at Marjory Stoneman Douglas High School in Parkland, which is a suburb of Fort Lauderdale. He is accused of entering the campus just before school was dismissed on Wednesday afternoon and opening fire on students and teachers.

Officials said another 14 people have been treated at area hospitals.

During a live press conference on Thursday afternoon, Sheriff Israeli identified 14 victims. He also presented a timeline from the shooting, saying that the suspect took an Uber to the school, opened fire into five classrooms, stairways and hallways, then left the school to buy a drink at Subway and went to McDonald's and shortly after was then arrested in Coral Springs. 

Sheriff Israel also said Cruz tried to mix in with a group of students when he fled the school. 

An attorney for Cruz says her client is sad and remorseful.

Public defender Melisa McNeill told reporters Thursday that Cruz is fully aware of what's going on but he's also just a "broken human being." 

She became emotional while speaking to reporters, saying she's fully aware of the impact the shooting has had on the community.

The leader of a white nationalist militia says Cruz was a member of his group and participated in paramilitary drills in Tallahassee.

Jordan Jereb told The Associated Press that his group wants Florida to become its own white ethno-state. He said his group holds "spontaneous random demonstrations" and tries not to participate in the modern world.

Jereb said he didn't know Cruz personally and that "he acted on his own behalf of what he just did and he's solely responsible for what he just did."

He also said he had "trouble with a girl" and he believed the timing of the attack, carried out on Valentine's Day, wasn't a coincidence.

Earlier, President Donald Trump addressed the nation in a live address and said he plans to visit Parkland.

Trump also issued a proclamation Thursday honoring victims of the shooting at the school.

The presidential proclamation says: "Our Nation grieves with those who have lost loved ones in the shooting at the Marjory Stoneman Douglas High School in Parkland, Florida."

Florida Gov. Rick Scott says he'll sit down with state leaders and work on how they can make sure people with mental illness aren't able to get guns.

Scott spoke Thursday a day after a shooting left 17 people dead at a high school. He said leaders will look at how they can make sure something like that never happens again.

FBI agent Rob Lasky says the FBI investigated a 2017 YouTube comment that said "I'm going to be a professional school shooter"; but the agency couldn't identify the person making the comment.

Authorities say the former student opened fire with an AR-15 rifle. 

Sheriff Israel says most of the fatalities were inside the building though some were found fatally shot outside.

SWAT teams were seen entering the campus with canines. A number of people could be seen being loaded into ambulances on a stretcher, reports CBS Miami. Students were seen being led across the street with their hands over their heads.

Students at the school were evacuated to West Glades Middle School.

A father of Marjory Stoneman Douglas student told CBS News: "My daughter, as of right now, is still trapped in a closet. She is afraid to speak. I told her 'don't call me, because I don't want no one to hear your voice,' so she is still trapped in a closet." 

"It's the worst nightmare not hearing from my daughter for 20 minutes, it was the longest 20 minutes of my life," Caesar Figeuroa also said.

The Coral Springs Police Department told teachers and students to remain barricaded inside until police could reach them.

Len Murray's 17-year-old son, a junior at the school where shooting was reported, sent his parents a chilling text: "Mom and Dad, there have been shots fired on campus at school. There are police sirens outside. I'm in the auditorium and the doors are locked."

Those words came at 2:30 p.m. Wednesday. A few minutes later, he texted again: "I'm fine."

Murray raced to the school only to be stopped by authorities under a highway overpass within view of the school buildings in Parkland.

Student Jeiella Dodoo told CBS News a fire alarm went off around 2:30 p.m. She said the school already had a drill earlier in the day.

Then, she said she heard about six gunshots. Everyone ran, and Dodoo described a chaotic scene as students fled. She said she hurt her toe while jumping a fence. She heard from a friend that people were being loaded into ambulances.

"That's when we knew it was really real, there was an actual shooter on campus," Dodoo said.

TV footage showed at least one person being wheeled to an ambulance on a gurney while emergency workers appeared to be helping others on the sidewalk. The news broadcasts also showed students running across the street.

(The Associated Press, CBS News contributed to this report.)

"On behalf of the Board of Trustees and staff members of the Washoe County School District, we extend our deepest sympathy to the students, staff, and families at Marjory Stoneman Douglas High School in Parkland, Florida following this terrible act of violence on their campus today.
We join with the people of Parkland in mourning the devastating loss of life that resulted from this tragedy. Teaching and learning should be the focus of every school day; violence and fear should have no place in a classroom.
We offer our thanks to the first responders who risked their lives to save children, bring comfort to the injured, and provide aid to everyone involved. We offer our prayers to everyone affected by this agonizing ordeal. And we join in solidarity with our fellow educators and staff members whose mission is to enlighten their students with the knowledge they need to lead peaceful, productive lives.
May they find peace in the aftermath of this unfathomable violence at their school."

--Board of Trustees President Katy Simon Holland and WCSD Superintendent Traci Davis