The two blasts, timed 15 minutes apart, killed 19 Christians, according to church and hospital officials. One body was unidentified. The attack, which occurred in the eastern Indonesian town of Tentena in Sulawesi Island, was the worst such incident in the nation since bombings killed 202 people in a Bali night club in 2002, according to Agence France Presse.
Vice President Jusuf Kalla told Metro TV on Monday that police had arrested two people who could "be used as witnesses to trace the perpetrators and the masterminds behind the bombing," according to the Associated Press.
No one has yet claimed responsibility for the attack, but Islamic militants responsible for previous attacks on Christians in Sulawesi Island are under suspicion. The region has experienced a series of attacks since a 2002 peace deal between Christians and Muslims ended a conflict that killed up to 1,000 people.
Vice President Kalla belives that the perpetrators of the bombings are trying to reignite sectarian violence.
"They want to stir up the conflict again because they know well that the people would be provoked," said Kalla.
A church leader called for calm among Christians.
"The terrorists want us to perform violent acts to return the region to chaos," said Rinaldy Damanik, the leader of the Synod Churches of Central Sulawesi. "We must stay calm," he said according to AP. However, shortly thereafter a mob stoned the town's only mosque.
The previous conflicts in Sulawesi Island and the nearby Moluccas Islands drew the attention of militant Muslim militias, including the group Jemaah Islamiyah, which has links to al-Qaeda.
In a news conference, Indonesian President Susilo Bambang Yudhoyono said he would find the attackers and bring them to justice.
"I ask the Indonesian people, especially our brothers in Central Sulawesi, to remain calm, and not to be provoked and agitated because we will handle this matter. We will find the perpetrators and punish them in accordance with what they have done," he said according to private El-Shinta radio in a report by AP.
There have been discrepancies regarding the actual number of dead. Vice President Kalla reported that 22 had been killed, while church and hospital officials reported 20.
Indonesia is the worlds most populous Muslim nation, where more than 90 percent of 210 million people are followers of Islam. About 8 percent are Christian, although Central Sulawesi has close has nearly equal numbers of Christians and Muslims.
Francis Helguero
Christian Today Correspondant