In Indonesia, three Christian schoolgirls have been beheaded and another was badly injured. The attacks happened on the island of Sulawesi, in an area that has a long history of violence between Muslims and Christians.

The girls were walking to school through a cocoa plantation near the city of Poso, in Central Sulawesi province, when they were attacked Saturday morning. Three were killed and a fourth was badly injured. Police say the heads were found some distance from the bodies.

It is unclear who was behind the attack. The girls attended a private Christian school, and one of the heads was left outside a church, leading to speculation that there was a religious motive.

Central Sulawesi Police Chief Oegroseno tells local station Metro TV that he believes common criminals would not have chopped off the girls' heads.

Susilo Bambang Yudhoyono (file photo)

President Susilo Bambang Yudhoyono Saturday condemned the killings, and called an emergency meeting with his vice president and senior security officials.

Central Sulawesi, and Poso in particular, was the scene of bitter fighting between Muslims and Christians in 2001 and 2002. More than 1,000 people were killed, before the government brokered a truce, and beheadings and the burning of bodies were not uncommon.

Although the violence has abated, it has never gone away completely. A bomb in May in the nearby town of Tentena, which is predominantly Christian, killed 22 people and injured more than 30.

The fighting four years ago attracted Islamic militants from all over Indonesia, and many remain in Sulawesi. Analysts have warned that violence could resurface at any time.

They say the militants have targeted Central Sulawesi, believing the region could be turned into the foundation stone of an Islamic state. Although Indonesia has the world's largest Muslim population, it is officially a secular nation.