SAN DIEGO -- A police officer driving with his cruiser's lights flashing and siren sounding got into a chain-reaction pileup at a busy Grantville intersection Monday, leaving the officer and another motorist with minor injuries.

The patrolman was heading east on Friars Road, responding to an auto-theft report, when his squad car crashed into a southbound Dodge truck at Riverdale Street about 8:30 a.m., according to police.

The impact sent the pickup spinning into another truck, which then was rear-ended by a blue sedan.

Medics took the officer and the woman who had been driving the Dodge to hospitals for evaluation of complaints of pain. Their injuries were not believed to be serious.

It was not immediately clear if the woman pulled out in front of the oncoming police car, possibly because she did not hear its siren or see its roof lights for some reason, SDPD Sgt. Sgt. Max Verduzco told reporters.

"We're going to be interviewing her at the hospital to see what happened," Verduzco said.

One of the people involved in the accident said he believed the officer ran a red light just before the collision, a local TV station reported.

Police can legally drive through stoplights while on urgent calls but "must proceed with due caution," Verduzco told the news station.

"And the way we like to do it is we like to make sure to clear each lane individually to make sure that we do have all vehicle traffic stopped so we can proceed safely," the sergeant said.

The accident forced the closure of the eastbound lanes of the thoroughfare and caused heavy congestion in the area through the late morning.