PINE RIDGE, S.D. — At least four people are dead after an apparent gas explosion at a duplex on the Pine Ridge Indian Reservation in South Dakota.

Tribal Councilman Richard Greenwald tells the Rapid City Journal that an elderly man and woman and two young women were killed in the blast Thursday afternoon. Authorities have not released any other details about the victims.

Tribal spokesman Kevin Yellow Bird Steele says the explosion happened in the town of Pine Ridge and that several injured people were taken to hospitals.

Steele says tenants in the duplex smelled propane gas and were searching for a leak before the explosion.

About 19,000 members of the Oglala Sioux Tribe live on the reservation, which at over 2 million acres is among the largest in the nation.