A man who admitted to burning down a Florida mosque once attended by the Orlando nightclub shooter has been jailed for 30 years.

Joseph Schreiber, 32, pleaded no contest to arson after setting fire to the Islamic Center of Fort Pierce at 12:30am local time on 12 September 2016.

During an investigation, St Lucie Sheriff's Office said they believed the fire was started deliberately and the date of the attack – close to the 15th anniversary of the 9/11 attacks in New York – was "in the back of our minds".

The arson of the attack also coincided with the Muslim holy day of Eid al-Adha.

The mosque was known to have been attended by Omar Mateen, the gunman who killed 49 people and injured dozens more at the Pulse nightclub on 12 June 2016 in what became the worst US mass shooting in modern history.

The mosque is also situated close to the apartment Mateen shared with his wife. However, Schreiber told police after his arrest the arson attack on the mosque had nothing to do with Mateen, according to assistant State Attorney Steve Gosnell.

Instead, police said he burnt down the mosque as he considered Islam to be a "national security threat". Schreiber also frequently posted Islamaphobic messages on Facebook.

Following his 30-year sentence, Sheriff Ken J Mascara said: "Finality like today brings the criminal justice system full circle. The men and women of the St Lucie County Sheriff's Office, along with our partners at the St. Lucie County Fire District, FBI, ATF, FDLE and Florida State Fire Marshal's Office worked tirelessly on this case and we thank them for their efforts."

Joseph Schreiber
Joseph Schreiber is pictured in this undated handout photo St. Lucie County Sheriff's Office/Handout via Reuters