Florida Governor Rick Scott calls on FBI director to resign over failure to probe school shooting tip-off

Florida Governor Rick Scott has called on the FBI director to resign after officials admitted they failed to follow up a tip-off about the Florida shooter that warned of his "desire to kill".

The bureau said a caller had contacted them concerned about Nikolas Cruz's gun ownership, erratic behaviour and his disturbing social media posts.

In a statement, the FBI said under normal circumstances the warnings would have been assessed as a potential "treat to life". But the information was not passed on to the Miami field office and no further action was taken.

"The FBI’s failure to take action against this killer is unacceptable," Governor Scott said in a statement.

"Seventeen innocent people are dead and acknowledging a mistake isn't going to cut it.

"An apology will never bring these 17 Floridians back to life or comfort the families who are in pain."

FBI Director Christopher Wray said the bureau was still investigating the incident. In a statement he said: "We have spoken with victims and families, and deeply regret the additional pain this causes all those affected by this horrific tragedy.

"All of the men and women of the FBI are dedicated to keeping the American people safe, and are relentlessly committed to improving all that we do and how we do it."

The FBI statement comes as the first funerals of the victims took place.

Separate services were held for Alyssa Alhadeff, 14, and 18-year-old Meadow Pollack at the Star of David Funeral Chapel in North Lauderdale, on Friday.

Cruz, 19, was charged on Thursday with 17 counts of premeditated murder after pleading guilty to the Valentine's Day gun massacre.

Louis Rodrigues, 14, a classmate of Alyssa Alhadeff, holds her funeral programme in his hand Credit: AP

Defence lawyer Melisa McNeill told reporters the teenager was a "broken human being" following the attack which left a further 15 people injured.

Cruz, a former pupil at Marjory Stoneman Douglas High School, shot students with an AR-15 style rifle in the hallways and school grounds before ditching his weapon and bullet proof vest and escaping among the crowds evacuating the building.

Among the dead was football coach Aaron Feis who shielded students from the bullets. And geography teacher Scott Beigel who was killed trying to protect his students by urging them back into the classroom away from the gunfire.

Students outside the Marjory Stoneman Douglas High School where Cruz killed 17 people. Credit: AP

The FBI has earlier confirmed it is investigating its handling of an apparent online threat the suspect is claimed to have made online last year.

Officers were tipped off about a comment on a YouTube channel last year, which read: "I'm going to be a professional school shooter."

Officials said officers carried out background checks but said they found "no indication of time, location or the true identity of the person who made the comment" and did not act further on it.