THE FBI has admitted it was told last month that the Florida school suspect could be plotting an attack, but agents failed to investigate.

A person close to Nikolas Cruz called the FBI’s public tip-off line on January 5 and provided information about his guns and his erratic behaviour, including his expressed desire to kill people and his disturbing social media posts.

The caller was concerned that Cruz could attack a school.

On Friday the agency acknowledged that the tip-off should have been shared with the FBI’s Miami office and investigated, but it was not.

FBI Director Christopher Wray – who was last night urged to resign by Florida Governnor Rick Scott – said the agency was still reviewing what went wrong. He said he was “committed to getting to the bottom of what happened” as well as assessing the way the FBI responds to information from the public.

Wray said: “We have spoken with victims and families and deeply regret the additional pain this causes all those affected by this horrific tragedy.”

The FBI was also notified about a comment on a YouTube video posted by a “Nikolas Cruz” last year. It investigated the comment but did not determine who made it.

Cruz has been charged with killing 17 people at Marjory Stoneman Douglas High School in Parkland, north of Miami, on Wednesday.

The US President Donald Trump has said he is travelling to Florida “to meet with some of the bravest people on earth”.

He is expected to thank first responders to the horrific high school shooting and also come face-to-face with parents, survivors and others, some of whom have angrily called for action to prevent future assaults.

The president tweeted that he will be meeting people “whose lives have been totally shattered”, but did not elaborate on his plans. White House officials have not said whether he would travel to the school.

Trump had already been slated to travel to Florida to spend the weekend at his Palm Beach estate, which is about 40 miles from Parkland.

He did not address the nation in the hours after Wednesday’s shooting but did deliver a sombre statement the following morning from the White House, directly addressing children who may feel “lost, alone, confused or even scared”.

“I want you to know that you are never alone and you never will be,” Trump said. “You have people who care about you, who love you, and who will do anything at all to protect you.”

In Florida, parents and a notable number of students are demanding action in addition to the usual offers of “thoughts and prayers”.

More than 1000 people attended a candlelight vigil on Thursday night near the school, and at one point some began chanting: “No more guns! No more guns!”

Trump, who frequently boasts about his support for the National Rifle Association, made no mention of gun violence or any new measure to restrict access to firearms during his Thursday remarks.

He did promise to tackle school safety and “the difficult issue of mental health”. He also tweeted that he was “working with Congress on many fronts”, but offered no details.

His latest budget request would slash Medicaid, the major source of federal funding for treating mental health problems, and cut school safety programmes by more than a third.

Last year, he signed a resolution blocking an Obama-era rule designed to keep guns out of the hands of certain mentally disabled people.