Nigerian church bombings kill 23 ABUJA, Nigeria, June 18 (UPI) -- Church bombings in Nigeria's Kaduna state killed at least 23 people, government officials said. A 24-hour curfew was imposed throughout the state to help prevent retaliation attacks on Muslims following the Sunday bombings, The Moment reported Monday. Five people were killed by a bomb at the Shalom Church in Triukania -- an army sergeant, two church security officials, a church member and a suicide bomber -- police said. At least 18 people were reported killed in two other church bombings. Authorities declined to offer details about the explosions, saying police were gathering evidence. "The state government considers this [curfew] to be necessary in order to avert further loss of lives and property in the state again," Kaduna Gov. Patrick Ibrahim Yakowa said. Police reported demonstrators crowded streets in two areas of Kaduna to protest the bombings, The New Agency of Nigeria reported.