Hunger strikes by immigrants and refugees are spreading at detention centers across Australia. But the Australian government says the strikes will not change its immigration policies.

The hunger strikes began last week in the Woomera detention center in the desert of central Australia. Asylum seekers from Afghanistan climbed onto the center's roof, holding up signs saying "freedom or death" and "release us or send us back."

After 12 days, more than 180 detainees, including nine children, are still refusing food. Thirty-seven people have also sewn their lips together to protest conditions at the center, and the length of time they have been held.

About 900 asylum seekers are incarcerated at Woomera, behind razor-wire fences, while their applications are processed. Some people have been imprisoned for more than two years.

The Australian government has agreed to speed up asylum application processing. But this concession has failed to end the protest at Woomera, which is spreading to other detention centers across the country, which hold 8,000 refugees.

Despite criticism from the United Nations and protest within the country, Australia's immigration Minister Phillip Ruddock says the policy of incarcerating asylum seekers will remain unchanged.