Three people were killed and four others were hospitalized following a multi-vehicle crash on the 10 Freeway in Ontario on Tuesday afternoon.

California Highway Patrol officers were called to westbound lanes of I-10 just west of the I-15 Freeway at around 1:15 p.m. after learning of the crash, according to the department's incident log.

It's unclear what led up to the crash, but police said three people were pronounced dead at the scene. Four others were taken to nearby hospitals for treatment. None of their conditions was immediately known.

A SigAlert was issued for all westbound lanes except for FasTrak, CHP officers said. The I-10 and I-15 connector road was closed as well, and drivers were advised to seek alternate routes due to "very heavy traffic and extended delays."

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