The Americans in matching T-shirts were greeted as heroes when they arrived one afternoon with clean water and medical care. But how the help got here was something the tsunami survivors could scarcely comprehend.

The forces of faith, fund-raising and globe-trotting volunteerism have opened a stream of private Christian aid to one of the most religiously conservative corners of Muslim Indonesia.

From the volunteers in a Ladong palm grove to aid provided by Samaritan's Purse (search), a group run by the son of evangelist Billy Graham, the initiatives show the power of church congregations to gather donations when tragedy strikes.

It also highlights the rising aspirations among a new style of Christian relief leagues mostly linked to evangelists and activists in the United States.

For decades, most U.S. faith-based relief agencies have followed a pact: access to government funds in exchange for promises not to seek converts or upset local customs. Even groups that don't take U.S. financial help are on board. Nearly all agree to a code of conduct that separates aid from religious outreach.

The tsunami disaster, however, has given a high-profile stage for other Christian groups outside the established framework.

It's still very rare for any church group to openly combine overseas assistance with missionary work — especially in the Muslim world. But it remains highly sensitive. Some Islamic leaders in Indonesia have warned of a sharp response to any Christian visitor accused of proselytizing.

Hasri Husan, a leader of the Islamic Defenders Front (search), a militant Muslim group that is operating a refugee camp in Banda Aceh, made his feelings clear.

"We will chase down any Christian group that does anything beyond offering aid," he said before making a slashing motion across his throat.

"We don't go around waving Bibles," said Ron Day, part of the 13-member team setting up water filtration and other provisions at a small refugee camp in Ladong, about 10 miles east of Banda Aceh, the hub of international relief efforts. "I know that is sometimes the perception. But it's wrong. As Christians, we are called to help others, but we don't insist that others believe what we do."

Day's group, Strategic World Impact (search), has become a rising force among the Christian aid brigades. SWI — run by veteran Christian rights campaigner Kevin Turner — offers war zone and disaster area training near its Bartlesville, Okla., headquarters.

When a crisis hits, it sends out the call to alumni in congregations around the country. Since the late 1990s, the teams have operated from Bosnia to Myanmar.

Day, a freelance video cameraman from Akron, Ohio, got the e-mail shortly after the tsunami struck Dec. 26. A business associate paid half his travel costs.

"We're here as aid workers, not missionaries," said Day, who attends a non-denominational church. "That being said, it's not impossible to think of someone we helped asking us to pray with them and we also saying, 'Of course, and you can also pray with us.'"

One of SWI's mission statements is "the evangelization of the world." Their T-shirts show a small rendition of their logo, a man holding a cross and a handful of wheat in the air.

This is where it could get complicated in northwestern Indonesia, a region of deep religious significance as the first part of the archipelago to come in contact with Muslim traders nearly 1,000 years ago.

The country's most influential group of Muslim clerics has warned they would "not remain quiet" if Christian groups step beyond offering aid. It's a threat taken seriously in a country where thousands have died in Christian-Muslim violence in recent years.

"This taxi driver asks me, 'Are you a fanatical Christian?'" said Steve Dawson, an SWI team leader from Tacoma, Wash. "I tell him, 'Well, maybe I am because Jesus says love your enemies and I love my enemies.' And then I say to him, 'I even pray for Usama bin Laden.'"

Terrorism has changed aid giving. Some of the conservative Christian leaders who have outraged Muslims also have mounted aid campaigns to Indonesia.

Evangelist Franklin Graham (search), the son of veteran preacher Billy Graham, called Islam "a very evil and wicked religion" following the Sept. 11, 2001, attacks.

His Samaritan's Purse relief organization sent a 747 cargo jet with medical and humanitarian supplies as part of a $10 million aid effort. The younger Graham toured battered coastal towns in Sri Lanka and Indonesia this week.

A team from evangelist Jerry Falwell's Liberty University (search) plans to travel to regions hit by the tsunami to bring supplies and "thousands of Gospel tracts in the language of the people," according to an announcement. In 2002, Falwell called the Prophet Mohammad a "terrorist" but later apologized.

Smaller Christian groups linked to evangelical churches also have joined the flow of tsunami help.

"Just when our nation's image in the Islamic world was improving as a result of the outpouring of American aid in the tsunami disaster area, we hear from those who would exploit the tragedy to advance their own extremist agenda," said Nihad Awad, executive director of the Council on American-Islamic Relations (search) in Washington.

Efforts such as Falwell's often have an uneasy rapport with more mainstream faith-based groups — nearly all agreeing to the U.S. funding rules blocking proselytization.

The American Council for Voluntary International Action (search), which represents more than 160 relief and development agencies, also has developed a set of standards for its members that indirectly discourages proselytizing.

"Nowadays, most people are thinking that Christian witness involves both word and deed so they are seeing this as a holistic ministry," Dudley Woodberry, an expert on Islam and Christian mission at Fuller Theological Seminary (search) in Pasadena, Calif. "In many cases, they are not allowed to proselytize so it basically has to be the ministry of deed."

But "certainly some people are using it as an entry strategy" for missionary work, he added.