PALU -- A home-made bomb exploded Thursday in the restive Indonesian town of Poso but caused no casualties, police said.

Police said the roadside bomb rocked the Sayo residential area at 1:30 a.m. (1730 GMT) and appeared to be designed to spread fear after years of relative calm in the area, which has been plagued by Christian-Muslim violence.

"There was no one injured and no damage," police spokesman Irfaizal Nasution said.

No one has claimed responsibility for the blast but Nasution said it appeared to be the work of an unidentified group which was "not happy if Poso remains in a peaceful condition."

The bomb was made with PVC casing and potassium. Police had interrogated two men but no one had been named as a suspect.

About 1,000 people were killed in violence between Muslims and Christians in Poso and the surrounding district in 2000-2001.

In 2005 Islamic militants were widely condemned after beheading three teenage Christian schoolgirls in Poso, which lies in Central Sulawesi.