ANTIOCH (CBS SF) — A toddler has accidentally drowned in her family’s backyard swimming pool in Antioch, according to authorities.

The Antioch Police Department said the drowning happened Wednesday evening at a home on the 4600 block of Durness Court.

Officers who responded to a report of a child who fell into her family pool arrived at the home found a two-year-old girl who was unresponsive, police said.

Both police officers and Contra Costa Fire Department personnel performed life-saving efforts on the girl. She was taken to a hospital where additional efforts to revive her were unsuccessful, police said.

The girl was not identified.