Colombo, April 27 -- Sri Lankan soldiers raided an eastern neighborhood early Saturday after a gunfight between troops and suspects linked to the Islamic State-claimed Easter suicide attacks killed at least two militants and one civilian, the military said.

Raids and police curfews shut down areas of eastern Sri Lanka as Catholic leaders canceled Sunday Masses indefinitely. Officials also urged Muslims to stay home for prayers in an extraordinary call by the clergy to curtail worship as fear of more attacks plagued the island nation.

The assault near Sammanthurai began Friday night after police tipped off soldiers to a suspected safe house, where militants set off three explosions and opened fire, the military said. At least three other...