UPDATE: Queensland Police Minister Jo-Ann Miller has expressed outrage and disappointment over the arson attack on the Toowoomba mosque.
Ms Miller was speaking from outside the West St mosque this afternoon.
"We are totally disgusted with it," she said.
"This is bipartisan. We want to make sure that whoever has been involved in this violent act is caught.
"We have come a long way in Australia. We have come a long way in Queensland and in Toowoomba and we will not tolerate this any more.
"This has been the second attack on this Islamic community in three months.
"It is shocking.
"It is outrageous and we want people to come forward so that police can get the names of people so they can be investigated and, if necessary, they are charged."
12.30PM: University of Southern Queensland Vice-Chancellor Jan Thomas says the suspicious fire at the Garden City Mosque is "not representative of the Toowoomba I know".
Ms Thomas said she had only known Toowoomba to be a "welcoming, community-minded and respectful place".
"What a shock then to hear of another case of suspected arson at the Toowoomba mosque," she said in a statement.
"If it is then this is not representative of the Toowoomba I know.
"Modern Australian society is rich in diversity and all the richer for it.
"Our differing experiences and differing perspectives positions our society to innovate, working together to solve problems and tackle challenges in clever ways."
Ms Thomas said while investigations were ongoing, the community must stand together.
"An attack on any of us is an attack on all," she said.
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11AM: Mayor Paul Antonio has expressed his shock over a suspicious fire that caused major damage at the Garden City Mosque overnight.
"I would suggest this is not what one would expect to happen in Toowoomba," Cr Antonio said.
"This is a community that is known for its cultural diversity and tolerance."
Cr Antonio is expected to release a statement later today.
9.30AM: Toowoomba mosque spokesman Professor Shahjahan Khan has spoken of the shock call he received this morning informing him of the structure fire.
It is the second suspicious fire at the mosque this year. Police are still to charge anyone over the arson attack in January.
"Of course it was a shock," Prof Khan said.
"What happened in January and now this.
"You cannot see from the outside but much of the inside is where it happened.
"It's burned to the ground."
Prof Khan said early discussions with investigating police officers indicated access was gained through a glass door that was smashed.
He said the Toowoomba International Food Festival planned for Sunday would go ahead.
"Because you cannot break our resolve and commitment to the community, and Toowoomba has shown again and again that they stand together," he said.
6.30AM: The mosque in Toowoomba has been substantially damaged in a fire overnight.
Emergency services were called to the mosque on West St about 1.50am following reports of a fire.
The blaze was extinguished, and the inside of the building has suffered major damage.
Police have declared a crime scene and initial investigations suggest that the fire is suspicious.
Police remain on the scene and investigations are continuing.