(CNN) -- Dozens of people seeking asylum in Australia after their boat crashed into cliffs along Christmas Island took part in two separate protests on the soil of their prospective home country, a spokesman for the Department of Immigration and Citizenship said Friday.
The demonstrators were protesting the conditions in their detention camp and claiming that the Australian Navy didn't do enough to save the lives of fellow asylum seekers. At least 28 people were killed when the boat smashed against rocks off the coast of the isolated Australian territory in the Indian Ocean, 1,600 miles northwest of Perth.
In the first protest, which started around 5 p.m., about 50 detainees in the Christmas Island Detention Center took issue with the lack of air conditioning in the compound, a result of a power outage across the island, Department of Immigration spokesman Steve Pivetta said.
In the second demonstration, as many as 70 protesters left the detention center and began a peaceful sit-in on the road out front to raise awareness of their fatal boat journey, Pivetta said. The detention facility is not a jail, so the detainees are free to walk outside.
Sky News Australia reporter Adam Harvey said security officers linked arms and surrounded the protesters, and set up a roadblock about 100 meters down the road.
Some of the demonstrators held signs asking why the Australian Navy hadn't done more to help when the boat crashed Wednesday, Harvey said.
Harvey said the asylum seekers had access to materials to make their protest signs. In addition, he said, detainees are able to watch television, so they knew that journalists were outside and they would have "the eyes of the world on them" if they protested.
"These people had a ready audience," Pivetta said.
Immigration has become a hot-button issue in Australia. Since winning the Australian federal election in September, Prime Minister Julia Gillard has adopted a tougher stance on asylum seekers, with plans to open more detention centers, including a proposed off-shore site on East Timor.
The people on board the stricken vessel off Christmas Island were of Iranian, Iraqi and Kurdish origin. An inquest and criminal investigation will determine the nature of the asylum seekers' deaths, their passage to Australia and the potential involvement of people smugglers.
"I believe it is vital that the truth, every fact, about this tragic incident is known to decision makers and to the general public," Gillard said during a news briefing in Sydney, calling the deaths "a terrible human tragedy."
CNN's Constance Cheng and Hilary Whiteman contributed to this report.