Officials are calling this an active investigation and it continues to be a traffic situation.
Police say two people were injured and taken to the hospital. One of them was an on-duty police officer for the Union City Police Department.
Traffic is still backed up all the way down Fremont Boulevard to Highway 880.
Fremont police tell me they were called to the intersection of Paseo Padre Parkway and Fremont Blvd. around 8:30 a.m. after getting a 911 call for a traffic accident involving injuries.
When they arrived they found three smashed vehicles including that of an on-duty Union City police officer in a marked vehicle.
The police officer along with the female driver of a four-door sedan and at least one of her two children were injured and taken to the hospital.
Officials say the officer's injuries are non-life threatening and he was released from the hospital. The female driver's injuries are moderate. Both she and the child remain in the hospital.
"The Union City officer was responding to an in-progress burglary call in Union City at the time of the collision," said Geneva Bosques with the Fremont Police Department. "The Union City officer was driving with lights and sirens activated at the time of the collision."
The third vehicle was occupied by a man who had stopped at the light at the time of the crash. The force of the impact from the police car and sedan sent the cars crashing into his van. He was not injured.
Officials expect to have the area cleared around 3 p.m. For now, it remains an active investigation.