The humanitarian crisis created by last month's earthquake and tsunami has drawn scores of relief organizations to Indonesia's Aceh province. Among them are several religious groups with radical agendas or controversial backgrounds.
A score of young men wearing rubber boots and green-and-white T-shirts snap to attention on the orders of their leader, who then begins passing out empty body bags on a street in downtown Banda Aceh.
They are volunteers of the Islamic Defenders Front, a radical Indonesian Islamist group best known for rampaging through bars in Jakarta that serve alcohol during the Muslim holy month of Ramadan.
Every day after morning prayers, hundreds of its volunteers dig through the tsunami rubble for dead bodies. They say they usually find 50 to 100 per day. Others go to neighborhood mosques to clean out the tons of rubble left by the waters.
One of the leaders of the group, Hasri Harahap, says its primary mission is humanitarian, because it is the duty of all who follow Islam to help their fellow Muslims.
He says that for a true Muslim, the disaster is a test from God. But for people who are not truly Muslim, who do bad things, this is not a test, but rather punishment from God.
He says the Front is doing some teaching in Aceh, but it mostly leaves that to other Islamist groups.
Another group with a reputation for violence is the Pemuda Panca Marga, an Indonesian youth group. Its leader, a tough looking man named Suhardi, says several hundred volunteers are here to help recover dead bodies.
He says it is important for Muslims to help each other, and notes that Islam requires a dead body to be buried.
There are also Christian groups working in this deeply traditional and devoutly Muslim province.
One of these, U.S.-based WorldHelp, recently launched an appeal for funds, saying it wanted to take 300 orphans from Aceh and place them in a Christian children's home in Jakarta.
The news brought protests from Muslim leaders, including the Secretary-General of the Indonesian Islamic Council, Din Samsudin.
"All domestic and international NGO's with hidden agendas can come in here with humanitarian proposals but there is another motive for proselytization of the Acehnese people and children,” he said. “This is what we don't like."
The group quickly abandoned its plans when it discovered that the government had banned the removal of orphans from Aceh.
Although most Christian groups say they are in Aceh for purely humanitarian reasons, some evangelical groups cannot resist displaying their devotion.
This angers people like Islamic Defender Hasri Harahap.
Imam Harahap says he is grateful for foreigners who come to help Aceh, but why put the slogan "Jesus is my God" on a box of rice, he says, or the words "My love is Jesus" on a T-shirt? Aceh is Muslim he says. When he sees such slogans he reports them to the authorities.
Under tents in a square in central Banda Aceh, two dozen volunteers from another controversial group, the Church of Scientology, operate what they describe as a trauma assistance center. They administer five-minute therapy sessions to tsunami survivors and relief workers who are unable to cope with what they have experienced.
Team leader Jean Davies of Australia says the sessions, called assists, consist of light massaging to relax jangled nerves, or exercises to shift the victim's focus from the trauma. Ms. Davies acknowledges Scientology is seen as controversial, but she says the volunteers are not trying to convert the Acehnese.
"They are completely at one with their faith here and it's beautiful,” she said. “I think that that's why they are doing so well. And we don't actually have any desire to be teaching this to anyone in a particular way."
Ms. Davies says the treatments require no equipment, and it takes less than an hour to train others. Her team has trained people from refugee camps, relief agencies and local hospitals.
Welfare Minister Alwi Shihab, who is overseeing relief efforts for the Indonesian government, says all these groups have government permission to work in Aceh.
"I don't think we are concerned about any ideological background,” said Mr. Shihab. “Whoever wants to help, regardless of his or her ideology or religion, is welcome. We are concerned about humanity, and humanity is beyond ideology."
Aceh is a traditional and devoutly Muslim region whose inhabitants are known for their suspicion of outside influences. As a result, longtime observers say these groups would have a difficult time changing the people's attitudes towards their faith.