Asylum seekers and other detainees at an Australian immigration center set fire to several buildings, climbed onto rooftops and hurled tiles at officials who were scrambling on Thursday to bring the chaotic protest to an end.
Up to 100 people being held at Sydney's Villawood Detention Center were involved in the riots, which began Wednesday night when two detainees climbed onto a roof, immigration officials said.
Protesters set an oxygen cylinder alight, which led to an explosion, and nine buildings _ including a medical center and dining hall _ were gutted by fire. Firefighters brought the blaze under control early Thursday and no one was injured.
Around 400 people are held at Villawood. Many of them are asylum seekers, but the facility also houses people who have overstayed their visas.
Some of the people involved in the protest were asylum seekers who had their visa applications rejected, Immigration Minister Chris Bowen said. Officials have not released details of the protesters' nationalities.
"If they think they will be accepted as refugees because of this sort of protest action, they have chosen the wrong government and the wrong minister because that won't be happening," Bowen told reporters in Canberra.
On Thursday, seven detainees remained on the roof of one of the complex's buildings, next to a large sign that read: "We need help."
Immigration department spokesman Sandi Logan said officials would not negotiate with the protesters until they came down off the roof. Criminal charges could be filed against the rioters, some of whom threw roof tiles and pieces of furniture at officials trying to get the blaze under control, Logan said.
"This is obviously unacceptable behavior that will have to be investigated," Acting Prime Minister Wayne Swan said.
Mohamed Alameddine, who lives across the street from the facility, said he heard a massive bang as the oxygen cylinder exploded, and the screaming and shouting of protesters and the riot squad.
"It was just like black fumes going up the sky. Buildings _ one after one _ they just went down," Alameddine, 17, told The Associated Press. "You could see the riot squad in there _ everyone was just going crazy."
Australia has seen a surge of asylum seekers fleeing Sri Lanka, Iraq and Afghanistan, and protests at detention centers have become relatively common. The influx has led to a heated political debate as opposition politicians blame the flow on a relaxation of immigration policies by the ruling Labor Party.