(Associated Press) – Unidentified attackers opened fire on two churches in Indonesia ‘s Central Sulawesi province on Sunday, injuring three people in the latest in a series of attacks on Christian targets in the region. The attackers, who were riding motorbikes, also hurled a bomb outside one of the churches in the town of Palu , causing minor damage, police spokesman Rais Adam said. Both buildings were packed with worshippers. Muslims and Christians fought bloody battles in Central Sulawesi in the late 1990s that killed more than 1,000 people. Large-scale violence has ended, but there still are sporadic attacks, mostly on Christian villages and places of worship. The attacks Sunday evening on the Protestant Emanuel and Anugerah churches occurred within minutes of each other. It was not clear whether the same group attacked both churches, which are about one kilometer (half a mile) apart.