A van reportedly carrying gas cylinders has exploded after being driven into the Australian Christian Lobby headquarters in Canberra on Wednesday night, setting the building alight.
There were no injuries suffered from people inside the building but the driver is being treated for his injuries in hospital.
ACT Policing said the van was carrying gas cylinders which were exploded at approximately 10.45pm. The vehicle was destroyed and the two-storey office building, named Eternity House, was badly damaged by fire.
The police later said in a statement they had established the actions of the 35-year-old male driver "were not politically, religiously or ideologically motivated".
ACL managing director Lyle Shelton posted two images online on Thursday morning of the vehicle outside the office in the inner-southern Canberra suburb of Deakin.
He also connected the incident to the ACL's staunch opposition to same-sex marriage and the Safe Schools initiative, labelling the apparent attack "unsettling" in the context of death threats being made against members of the organisation.
"I think something of this nature, that appears to be so deliberate, is an attack against the sort of things that we've been saying in the public square," he told ABC radio.
"And obviously someone didn't like that which we stand for, which we've advocated publicly."
He also suggested that rhetoric from politicians who had portrayed the ACL as a hate group motivated "unhinged" people to act violently.
The ACL has regularly clashed with leading advocacy groups like Australian Marriage Equality.
Alex Greenwich, the co-chair of AME, called the incident "shocking and saddening".
"Thoughts and prayers are with everyone at the Australian Christian Lobby," he tweeted.
Australian Capital Territory Police confirmed an investigation was under way into the incident.
"ACT policing responded to an incident last night where a vehicle collided with a building in Deakin," a spokesman said. "The driver was the only person injured in the collision. Investigations are ongoing."
"There are no public safety issues and ACT Police are seeking any witnesses to the incident."
Two police officers and a member of a private security firm were stationed outside the building on Thursday morning overnight, but had left the scene by 7.30am.
Outside the building, shattered glass covered the ground and the concrete was scorched with burn marks, while a strong chemical smell remained in the air.
The outside of the two office rooms on the ground floor was seriously damaged, while there appeared to be major damage to the top floor and the inside of the building.
Comment has been sought from the ACT Ambulance Service and the nearby Canberra Hospital.