"How do we make sure that individuals with mental illness never touch a gun?" says Governor Rick Scott.

The Republican adds that lawmakers in Tallahassee, the state capital, must sit down to have "a real conversation" about gun control and mental illness.

"The violence has to stop. We cannot lose another child in this country to violence in a school," says Governor Scott.

The sheriff in Florida says that there have been a number of "fictitious" calls to schools today which distract police and spreads investigators thin.

He called the copycat calls "so pathetic".

"Today's not easier than yesterday was," Sheriff Scott Israel said as he began his press conference.

"All the victim's families have been notified," he said, calling it a “daunting challenge”, but adding that it was “the right thing to do”.

He said that in the coming weeks, "I'm going to be very animated about what I think this country can do" to prevent future tragedies.

Attorney General Jeff Sessions, commenting on the shooting, said: "This situation that we're seeing just cannot continue."

"We will take such action as we are able to take. We have to reverse these trends that we are seeing in these shootings."

"We are once again, watching the images of children— terrified— streaming out of their school, hands over their heads. It's image we don't need to continue to see. When parents, once again, go to sleep fearful that their kids will not be safe when they go to school," said Mr Sessions.

"It cannot be denied that something dangerous and unhealthy is happening our country," he added.

Fox News noted that Mr Sessions addressed the country's gun laws, saying: "It's not good if we've got gun laws that say criminals can't carry guns that never get enforced."

However, it is believed that the suspect, Nikolas Cruz, used a legally purchased AR-15 semi-automatic rifle in the attack.

Mr Sessions was speaking at the Major County Sheriffs of America conference.

It was 14:30 when David Hogg heard the first shot.

The 17-year-old was in environmental science class at Marjory Stoneman Douglas High School in Florida. The teacher had just passed out worksheets.

When he heard the bang, his classmates turned to each other. That sounded like a gun, they said.

The teacher closed the door. Within seconds, the fire alarm went off.

"We instinctively walked outside," says David. "We thought it was a drill."

As David's class walked towards the evacuation zone, they saw a "tsunami" of people running towards them. They turned and followed the crowd down the corridor.

What they didn't realise was this: they were heading towards the shooter.

"A very heroic janitor stopped us," says David. "He said, 'Don't go that way - he [the shooter] is over there'."

• Read David's full story here.

In the wake of the tragedy, many people have been expressing their condolences in the usual fashion - with "hopes and prayers".

But some people - including actress Elizabeth Banks - have criticised the sentiment.

Many celebrities on social media have said that without actions and policy change, well wished amount to little.

Read our full piece for comments from Mark Ruffalo, Stephen King, and Kim Kardashian West.

At first, it seems like a normal day in Parkland, Florida.

The sky is blue. The palm trees are green. And the temperature is rising.

But, on approaching Stoneman Douglas High, it’s clear that nothing is normal about today.

The yellow school buses are parked up, going nowhere. The soccer fields are empty. TV trucks line the neat verges.

While the high school is closed, the nearby elementary school is open. Parents hold their children’s hands tightly as they dodge cameramen.

Lanny James, 77, has a place five miles away in Margate. He comes here for the sun; today, the temperature is 25C by 9.30am.

He was playing golf when he heard the news. "I just love South Florida," he says. "This is supposed to be paradise."

Lanny, a semi-retired broadcaster, has 10 guns and has hunted since the 1960s.

"I just don’t know what the answer is," he says. "And there may not be one."

The morning after yet another fatal school shooting in the United States, Florida is mourning the victims.

We'll continue to provide updates on our live page. To catch up:

• Read our main story: Teachers 'were warned' about Nikolas Cruz
• Learn what we know about the suspect so far
• Read some of the stories of "fear and panic" from students

As we wrap up, here are the key facts:

• at least 17 dead
• more than a dozen wounded
• a 19-year-old former pupil in custody
• he had an AR-15 style weapon

As the story develops, we will continue to update our main story here.

The suspect is a 19-year-old who was expelled from the school.

His name is Nikolaus Cruz.

He was armed with an AR-15 rifle and had “countless magazines”.

The shooting spree began outside the school and continued inside.

Broward County Sheriff Scott Israel just told reporters the new death toll.

At least 12 people were killed in the shooting, according to US media reports.

Nikolaus Cruz, 19, has been named as the suspect in the Florida school shooting, according to US media reports.

The suspect reportedly pulled the fire alarm and caused chaos in the school before he started shooting, law enforcement officials told CBS News, external.

The Broward County Sheriff previously said that Cruz had been a former student.

A student says in an interview that the suspect was well known for being a troubled kid.

A local reporter captured footage of a group of police officers swarming the suspect to arrest him.

The sheriff adds that they believe all students are now out of the school, but there is a chance there may still be wounded children hiding in the building.