Florida shooting: Updates as they happened

The FBI has started an "extensive" review of how it handled a tip-off last year related to suspect Nikolas Cruz to see if any mistakes were made, Reuters news agency reports, citing a law enforcement official.

Earlier, it was revealed that a comment on YouTube - apparently from Mr Cruz - saying "I'm going to be a professional school shooter" had been reported to the FBI tip hotline.

The FBI said that, at the time, "no other information was included with that comment which would indicate a time, location or the true identity of the person".

Ben Bennight, the YouTube user who spotted the comment, said he had been interviewed by FBI agents last year - but there was no follow-up. He was interviewed again in the wake of the shooting.

He posted a video blog late on Wednesday about the story.

Screenwriter Bess Kalb, who writes for Jimmy Kimmel Live, has been singling out senators who are tweeting their condolences - by responding with the amount of money they have received from the National Rifle Association (NRA):

• Read the full piece from BBC Trending here

Suspect Nikolas Cruz was a member of white nationalist group Republic of Florida (ROF), its leader said.

The Anti-Defamation League first reported the connection, saying it had followed up online posts about the link by calling the ROF's leader, Jordan Jereb.

"Jereb said that Cruz was associated with ROF, having been “brought up” by another member," the ADL wrote in a blog post.

"Jereb added that Cruz had participated in one or more ROF training exercises in the Tallahassee area, carpooling with other ROF members from south Florida."

The same information was then confirmed by the Associated Press.

But the ROF said Cruz acted independently and the attack was not linked to the organisation.

The claims have not been verified by any law enforcement agency.

Vigils for the victims of the shooting are being held across Parkland today.

BBC reporter Owen Amos is live at one this afternoon:

Broward Sheriff's office, which oversaw the police operation at the school, has just tweeted this reminder of another vigil for the victims at 18:00 local time (23:00 GMT):

Jaime Guttenberg FacebookCopyright: Jaime Guttenberg Facebook

Family and friends of the 17 victims are slowly naming their lost loved ones on social media.

Jaime Guttenberg's parents announced that their daughter was killed in a Facebook post.

Yesterday, "we lost our baby girl to a violent shooting at her school". Our son Jesse "lost his sister," the post read.

Read more about the victims of the shooting.

Getty ImagesCopyright: Getty Images

Former President Barack Obama took to Twitter to offer his condolences to the victims of the mass shooting in Florida.

Mr Obama, who considers the mass shooting at Sandy Hook one of the worst moments of his presidency, said he was grieving - but reminded Americans that "we are not powerless".

He encouraged the creation of "common-sense gun safety laws that most Americans want".

BBCCopyright: BBC

I was going to the bathroom to refill my water bottle when I heard the fire alarm... when I got back we started to evacuate...

We got as far as the bottom half of the stairs when the administrators started shouting at us to get inside.

At this point, we thought it was a real fire. We were directed to a different classroom, and were sent straight to a supplies closet.

We were still unsure about what was going on... we barricaded ourselves in to the closest after about 20 minutes, with a ton of desks and cables.

They came in with guns... they told us to put our hands up, and we filed out of the closet. Outside the classroom, there were even more police.

Once we got outside into the clearing and saw all of the police we got a sense of just how big this was.

I'm still in shock.

I will go to one of the vigils that is happening later at the Parkland Recreation Centre with a group of my friends.

None of my close friends were killed or injured, but some people who I know from some of my classes have been.

I feel like I have to cry but I haven't been able to.

"The Baker Act in Florida allows law enforcement or medical professionals to confine a person involuntarily while they get examined and looked at," said Sheriff Israel, adding that officers must prove that the person is a threat.

"What I'm asking our lawmakers to do... is give police the power, if they see something on social media - if they see pictures of rifles, and blood and gore and guns and bombs - if they see something [like] horrific language.

"If they see a person talking about 'I want to grow up to be a serial killer' - we need to have the power to take that person and bring them before mental health professionals at that particular time, involuntarily, and have them examined."

Getty ImagesCopyright: Getty Images

Democratic Senator Bill Nelson - from Florida - addressed the Senate floor on Thursday and called for gun control.

“At some point we as a society has got to come together and put a stop to this,” he said.

“I have hunted all my life. I have had guns all my life. I still hunt with my son. But an AR-15 is not for hunting, it’s for killing," he continued.

He asked: "When is enough going to be enough?"

"Sandy Hook Elementary: 20 students killed. That wasn't enough.

"The Pulse nightclub in Orlando - 49 people killed. That wasn't enough.

"Las Vegas - 58 people killed. That wasn't enough.

"Now this high school - 17 killed. Some as young as 14 years old. When is enough going to be enough?"

Just before Mr Trump's speech, the BBC's White House reporter spoke to the Center for American Progress advocacy group, which accused his administration of having close ties to the National Rifle Association.

After Mr Trump's remarks, she pointed out one of his previous speeches made clear his relationship with the gun rights group:

During his address to the nation, Mr Trump also said he was making plans to visit Parkland, Florida.

He has not yet provided a date.

During the press conference, Superintendent Robert Runcie said: "Students have been reaching out to me, to staff, to board members...saying now is the time for this country to have a real conversation on sensible gun control laws."

"Our students are asking for that conversation. I hope we can get it done in this generation. And if we can't, they will."

In regard to the shooter's mental health he said the school district had been trying to get Cruz support while he was a student.

He added: "This is bigger than just the school system. We need a community wide approach to helping our students with challenges and mental health concerns. We need to invest resources, because if we don’t it’s not a question of if, it’s a question of when [it will happen again].”

During a press conference, FBI agent-in-charge Robert Lasky confirms agents investigated a suspicious YouTube post in which a commenter with the same name as the suspect posted about his desire to become "a school shooter".

"The comment simply said 'I'm going to be a professional school shooter," said Agent Lasky.

"No other information was included in that comment which would indicate a time, location or the true identify of the person who made the comment.

"The FBI conducted database reviews - checks - but was unable to further identify the person who actually made the comment."