Muslim radicals are handing out Qurans (search) with the bags of rice and sugar they distribute to tsunami victims. Christian aid groups have also rushed in, quietly promising salvation in this predominantly Islamic region but fearful their presence could spark sectarian violence.
Across the Indian Ocean basin, dozens of faith-based groups have joined relief efforts in the wake of last month's tsunami (search), which killed more than 155,000 in 11 countries and left millions homeless.
The groups include everyone from Al Qaeda-linked militants to evangelical Christians, and their presence is most profound in Indonesia, where the needs are greatest and the cash-strapped government has thrown open the doors to foreign aid groups.
The heavy Muslim influence in Aceh province — one of the few Indonesian regions that has instituted Islamic law — has defined how the groups operate. While Muslims are bragging about their religious credentials, Christian groups are mostly invisible and instruct workers not to display their church names or wear crosses.
"We prefer to address the physical needs first," said William Suhanda, an Indonesian whose Christian group "Light of Love For Aceh" (search) is helping distribute food in Banda Aceh, the provincial capital, and wants to bring 50 children to a Christian orphanage in Jakarta, the national capital.
"We also want to expose them to Christian values," he said. "It is so they can see the other side, that we're about the love of Christ. But this is not the place to carry a Bible."
But evangelists like Wisconsin native Mark Kosinski say it's impossible to separate relief activities from sharing the Gospel. He acknowledged he was warned to tone down his message but says he has "a job to do."
"These people need food but they also need Jesus," said Kosinski, who arrived this week from Malaysia. "God is trying to awaken people and help them realize that salvation is in Christ."
One Virginia-based ministry considered airlifting 300 orphans waiting at the Banda Aceh and Medan airports to a Christian children's home in Jakarta. WorldHelp (search) started raising funds for the operation until it learned that the government banned non-Muslims from adopting Acehnese orphans.
"What we were attempting to do in finding a home for these orphans is no different from what Mother Teresa did in placing Hindu orphans in a Christian children's home," said Vernon Brewer, president the ministry.
The collection of religious groups in this conservative Muslim city, which has only five churches, has raised the possibility of sectarian violence but has also led to some unusual partnerships.
The Islamic Defenders Front (search) — known for trashing Western pubs in Jakarta — spent much of this week removing corpses from collapsed homes alongside an Indonesian Christian group. Mormons have teamed up with Islamic relief operations to send aid to the region.
The United Nations asked the extremist Muslim group Laskar Mujahidin, which allegedly has links to Al Qaeda and has been accused of killing Christians in an earlier conflict, to unload a plane of relief supplies late Wednesday because it was short of personnel.
"Everyone wants to help in this catastrophe and prejudices are put aside," said Mans Nyberg of the United Nations High Commissioner for Refugees. "Of course, they are serving a role."
Still, the dozens of refugee camps have in some ways become the battleground for religious groups. Muslims especially appear to have filled a void left by the government and quickly set up medical clinics, opened schools and are providing much of the food and medicines for tens of thousands of refugees.
"We need religion. We need to remember our God," said Sari Andina, a 23-year-old teacher whose camp features a mosque where children are taught Islamic studies.
The most prominent Muslim group is the Justice and Welfare Party, a political party that has become popular with its message of morality and clean government. Nearly 2,000 volunteers — wearing the party's black and yellow — arrived days after the disaster and are a common sight driving around the city or unloading tons of aid at the airport.
For party members like Jamy, the Dec. 26 tsunami was a warning for Muslims. He and other volunteers say that another disaster is inevitable unless people start living according to the teaching of the Quran.
"We tell them this came from God and we have to be strong," said Jamy, who like many Indonesians uses only one name. "This is some kind of a lesson. People forgot about God and he has now punished them. Maybe now people will realize what they have done and start going to the mosque."
The task is more complex for Christians because they have often been a target of violence in Indonesia, partly over allegations they were attempting to convert Muslims.
Since the fall of the dictator Suharto in 1998, thousands of churches have been bombed and burned. Fighting between Muslims and Christians has killed thousands in the provinces of Central Sulawesi and the Malukus islands.
"Any time you have a strong Muslim community and concerns about Christianization, there is going to be conflict," said Eddy Rubble, a North Carolina Christian who is volunteering here. "I'm afraid that after months of people helping one another survive, it will only take one spark to create a big issue."