SAN FRANCISCO - A police officer of California Highway Patrol (CHP) was killed when an "errant driver" drifted off the road from Interstate 880 highway and slammed into the patrol vehicle parked nearby, the CHP said Monday.

The 33-year-old CHP officer, Andrew Camilleri, lost his life when he was about to go home for a Christmas reunion with his wife and children just hours from getting off duty, the CHP said.

His partner, Jonathan Velasquez, was also injured in the car crash and received treatment at a hospital for lacerations.

The CHP said the patrol car of the two police officers was struck in the right rear by the impaired driver in the North Bay Area north of San Francisco on the US west coast.

"Today is not a holiday for the Highway Patrol. Today is about a tragic loss of one of our own, one by the name of Andrew Camilleri, who we will consider a hero now and forever," CHP Assistant Chief Ernest Sanchez said at a news conference Monday.

The driver, a 22 year-old man who caused the fatality, also suffered serious injuries and was suspected of driving under the influence of alcohol or drugs, said the police.

California police have beefed up security and patrol on highway during the Christmas period, a few days after local media reported last Friday that the Federal Bureau of Investigation (FBI) had foiled an attempt to blow up Pier 39, a shopping center and tourist attraction in San Francisco.