BEKASI, Indonesia (AP) — Indonesia's president ordered police to hunt down and arrest 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.

No one claimed responsibility for Sunday's attacks. But suspicion immediately fell on Islamic hard-liners who have repeatedly warned members of the Batak Christian Protestant Church against worshipping on a field housing their now-shuttered church.

In recent months, they have thrown shoes and water bottles at the church members, interrupted sermons with chants of "Infidels!" and "Leave Now!" and dumped piles of feces on the land.

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.

She said the face of one of the assailants looked familiar.

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 to hold accountable those responsible.

"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."

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 in recent years.

Leading the charge against the Batak Christians has been the Islamic Defenders Front, which is pushing for the implementation of Islamic-based laws in Bekasi and other parts of the nation.

They are 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.

The front also pressured local authorities early this year to shutter the Batak church, located in a densley populated Mulsim 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.