Bekasi, Indonesia - Indonesia's president ordered police to arrest the assailants who stabbed a Christian worshipper in the stomach and beat a minister in the head with a wooden plank as they headed to prayers.
Neither of the injuries appeared to be life-threatening.
Indonesia, a secular country of 237 million people, has more Muslims than any other in the world. Though it has a long history of religious tolerance, a small extremist fringe has become more vocal - and violent - in recent years.
President Susilo Bambang Yudhoyono, who relies heavily on Islamic parties in parliament, has been widely criticized in the media for failing to crack down on hard-liners.
But he immediately called on authorities to investigate and hold accountable those responsible for Sunday's attacks.
Police have said they know who the perpetrators were, though they would not comment further. Suspicion immediately fell on the Islamic Defenders Front, Muslim hard-liners who have repeatedly warned members of the Batak Christian Protestant Church against worshipping on a field housing their recently shuttered church.
But the front, which is pushing for the implementation of Islamic-based laws, denied involvement in the attacks, ordering its followers to help police investigation, group leader Rizieq Shihab told reporters.
The front is known for smashing bars, attacking transvestites and going after those considered blasphemous with bamboo clubs and stones. Perpetrators are rarely punished or even questioned by police.
In the last few months, they have thrown shoes and water bottles at church members, interrupted sermons with chants of "Infidels!" and "Leave Now!" and dumped piles of feces on the land.
"We've questioned nine witnesses and have already identified the perpetrators," said local detective, Capt. Ade Arie. "But it's too early to comment or speculate on a motive."
Local Police Chief Imam Sugianto said Asia Sihombing, a worshipper, was on his way to the field when assailants jumped off a motorcycle and stabbed him in the stomach.
The Rev. Luspida Simanjuntak was smashed in the head as she tried to come to his aid.
"I was trying to help get him onto a motorcycle so we could get him to a hospital," she told reporters in the industrial city of Bekasi, 25 miles (40 kilometers) east of Jakarta.
The Islamic Defenders Front pressured local authorities early this year to shutter the Batak church, located in a densely populated Muslim area, saying the permit was granted without the required approval of residents.
The Christian worshippers have refused to back down. Every week, about 20 or so return to the field to pray, defying threats and intimidation.
Most people in Indonesia practice a moderate form of Islam and abhor violence. But the Setara Institute for Peace and Democracy, a human rights group, said attacks on religious freedom by hard-liners were steadily increasing.
It said there have been 64 incidents - ranging from physical abuse to preventing groups from performing prayers and burning houses of worship - in 2010, up from 18 in 2009 and 17 in 2008.
"It's largely because Yudhoyono's administration is always so slow to step in," said Hendardi, a Setara activist, pointing to recent attacks on the Islamic minority sect, Ahmadiyah.
"If he doesn't take immediate steps to address this problem, then the blame lies with him."