An explosion shook a government building in the main town of Indonesia's restive Poso district on Sulawesi island, but police say no one was hurt.

Local police say the blast, believed to have been caused by a home-made bomb, slightly damaged the office of a state social welfare group in Poso town.

They say the blast shattered several windows and part of the ceiling.

There has been intermittent violence between Muslims and Christians in the Poso district for more than two years.

Between 500 and one-thousand people were killed and tens of thousands made homeless before a peace deal went into force last December.