ACT police have confirmed the van that exploded outside the Australian Christian Lobby offices in Canberra on Wednesday night was detonated by the driver but have ruled out political motivation as a reason.
Speaking to the media on Thursday, Deputy Chief Police Commander Mark Walters said the driver appeared to have ignited gas cylinders inside the vehicle about 9.30pm.
The resulting explosion damaged the vehicle and building.
"As a result of our conversations with this man, we've been able to establish that his actions were not politically, religiously or ideologically motivated," Mr Walters said.
He said the driver, a 35-year-old man from the ACT, walked with serious burn injuries to Canberra Hospital, where he was briefly interviewed by police before treatment continued.
An ACT Health spokeswoman confirmed the man was in a "critical condition".
He was not previously known to police.
The driver is understood to have parked the van outside the ACL's headquarters in Deakin before causing the explosion.
Mr Walters said the investigation was ongoing but could not confirm the ACL had been the target. Police said they had spoken to the man's family but didn't provide details of the conversation.
Earlier on Thursday morning, Australian Christian Lobby managing director Lyle Shelton said the incident was an attempt at political intimidation.
"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," Mr Shelton told ABC radio.
He also suggested that rhetoric from "extreme left" politicians who had portrayed the ACL as a hate group motivated "unhinged" people to act violently.
When asked to respond to the police statement, Mr Shelton told Fairfax Media that the explosion came against a backdrop of abuse and death threats levelled at the ACL.
"It's all very sensitive, we don't know the motives of the person last night; we hope it's not related," Mr Shelton said.
"Obviously I respect what the police have to say. I'm not sure how they can know for sure."
Mr Walters reassured the community that there was no concern for public safety.
"Police are conducting a thorough investigation and there is no threat to public safety.
"We want the Canberra community to go about their business today reassured that ACT Policing is working to establish the circumstances surrounding this incident," he said.
The investigation would include previous threats to the ACL.
Police urge anyone with information to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website. Please quote reference 6049560. Information can be provided anonymously.
with Bevan Shields