WAUSEON, Ohio (AP) — A father and daughter were killed in a house explosion early Thursday in a northwestern Ohio community, authorities said.

It was not clear what caused the blast, which occurred around 5:30 a.m. in Wauseon and also injured two other people. The explosion sent smoke spewing from the home, and large amounts of debris were spread across the front yard.

A witness told WTVG-TV that he and some other people pulled a woman and her son from the home. They were being treated at a hospital for undisclosed injuries.

Authorities at the scene said the woman’s husband and their daughter were killed in the blast.

Wauseon is about 43 miles (69 kilometers) west of Toledo, near the Michigan border.