JAKARTA -- Karina is an atheist, but her friends jokingly call her "the prophet." That is because she is helping nurture a community for unbelievers in predominantly Muslim Indonesia, where trumpeting one's disbelief in God can lead to abuse, ostracism and even prison.
"It's very normal for atheists to be paranoid because the environment does not support them," said Ms. Karina, 26, who uses only one name. But, she said, "in this group people don't need to be afraid."
Indonesian Atheists was founded with a Facebook page in 2008 and now holds regular gatherings. The Internet has offered its members a safe space to air their opinions, and the feeling of community has made them braver about gathering in public. But recent prosecutions of people who made online comments deemed blasphemous by the country's courts have stoked fears that they too could come under attack.
"Members' growing outspokenness and courage does not indicate that other people increasingly accept us," said Karl Karnadi, 29, the group's founder. He lives in Germany and is candid about being a nonbeliever on Facebook and Twitter. Inside Indonesia, atheists are circumspect about their views, he said, and refrain from public criticism of Islam or any statements that could run afoul of the country's blasphemy law. Still, he said, that is an advance from a time when people were fiercely secretive.
"At first people think they're alone," Mr. Karl said in a Skype interview. "But after we meet each other, we feel like we're accepted. We're together if anything happens to us, and that feeling of community is very valuable."
While the Indonesian Constitution enshrines freedom of religion, legal protection is afforded only to six official faiths -- Islam, Protestantism, Catholicism, Buddhism, Hinduism and Confucianism. Citizens are required to list their religion on national identity cards. Violating the country's blasphemy law by insulting or interfering with the practice of one of the official faiths can bring a five-year prison term.
Concerns about the application of that law against religious minorities have risen amid an increase in religiously motivated violence that rights campaigners say is threatening a tradition of tolerance in Indonesia.
A recent report by the New York-based Human Rights Watch said reported cases of religious violence in Indonesia had increased by 20 percent since 2010. The Setara Institute, a research organization based in Jakarta, documented 264 attacks on religious minorities last year.
Those perpetuating the violence are largely militant Islamists who have an "uncompromising view of religious purity," said Phelim Kine, a deputy Asia director of Human Rights Watch. "Compounding that is a complete failure by the Indonesian government to confront this violence and put a stop to it."
Officials say that while, under the Constitution, each citizen is entitled to whatever private belief he chooses, religious activities outside the home must be controlled by the state to maintain public order.
"Someone who belongs to one particular religion has also to respect other religious communities," said Nur Kholis Setiawan, head of the center for research and development of religious life at the Ministry of Religious Affairs. "The state has an authority and an obligation to manage religious life in the public forum."
It has done so, however, through several regulations that Mr. Kine says have been used against religious minorities, including a ministerial decree that has prevented Christian groups from opening churches and the 1965 blasphemy law, which courts have used more than a dozen times since 2005 to prosecute Shiites, Christians and atheists.
Last year Alexander Aan, a civil servant in West Sumatra, was charged with blasphemy for posting "God does not exist" along with cartoons of the Prophet Muhammad on a Facebook page he administered dedicated to atheism. Months later another man, Sebastian Joe, was charged under the same law for insulting Islam, also on Facebook.
Both men were eventually sentenced to prison under a separate electronic communications law that prohibits the transmission of defamatory information through the Internet. Mr. Alexander was sentenced to two and half years for "disseminating information aimed at inciting religious hatred." Mr. Sebastian was sentenced to five years.
A report by the International Humanist and Ethical Union, a global organization representing atheists and freethinkers, listed Indonesia among a number of Muslim-majority countries, including Bangladesh and Egypt, that have stepped up prosecution of religious expression in social media. According to the group, which submitted its report to the U.N. Human Rights Council on Feb. 25, more than a dozen people, in 10 countries, were charged with "blasphemous" statements on the Internet in 2012.
Despite concerns about attack or arrest, Ms. Karina is among the more than a thousand members of Indonesian Atheists, many of who are increasingly speaking out. In 2011 some members started another group, You Ask Atheists Answer, a forum that aims to facilitate discussions about atheism in the hope of breaking down hostile stereotypes.
Because the forum is open, many Indonesian Atheists members use aliases to post comments that might offend militant Islamists who have attacked those they consider apostates.
Members' paths to atheism have varied. Some say they are from families whose unbending embrace of religion caused them to rebel, others say their more moderate upbringing allowed them to question religion's role in their lives. Most say the Internet has been a gateway to readings and discussions that have affirmed their disbelief.
Offline, they say the group is more than a collection of like minds. It is a source of friendship, a support network and a safety net. When Muhammad Ikhwan, who goes by Matthew Edison because his birth name is "so Islamic," needed money to repay a debt to his estranged father, he said members collected 30 million rupiah, or about $3,000, to help him.
As the community has grown, however, so has the attention. An administrator of You Ask Atheists Answer said that he receives death threats and frequently gets messages demanding that he dissolve the group. He now uses a pseudonym on Facebook.
Some atheists say that if militant Islamists can violently attack other Muslims they deem heretical -- referring to raids on Shiite villages and members of the Ahmadiyah sect -- worse things could happen to them. "We cannot expect that the government will protect us," Mr. Edison said.
In February 2011, for example, hundreds of militant Islamists attacked an Ahmadiyah community in West Java and beat three people to death. A district court sentenced 12 of the perpetrators to jail terms of three to six months. The following month the same court sentenced an Ahmadiyah man wounded in the attack to six months in jail for inciting the violence. More recently, officials in Bekasi, West Java, sealed an Ahmadiyah mosque in a crackdown on what they called a "deviant" branch of Islam.
"The government is doing something wrong by not protecting constitutional rights," said Philips J. Vermonte, a researcher at the Center for Strategic and International Studies in Jakarta. The state has an obligation to defend the rights of minorities, he said. "But that's what we don't have right now in Indonesia."
Mr. Karl, who said he had gradually renounced Christianity after years of reading books about science and religion and disillusion with religious groups who use faith to justify intolerant behavior, says that, as long as the law is used to attack those outside the religious mainstream, Indonesian atheists should be careful.
In the meantime, said Ms. Karina, group members will continue to gather, in the manner she applies to her own life. "I'm open," she said, "but I'm not broadcasting."
This article originally appeared in The New York Times.