FREMONT, Calif. >> A gunman suspected of shooting and wounding two Northern California police was holed up in a house early Thursday in an armed standoff with law officers, authorities said.

Officers fire tear gas into the house, but he was still refusing to end the standoff, Sgt. Ray Kelly of the Alameda County Sheriff’s office said.

The officers from the Fremont Police Department were shot Wednesday afternoon after a traffic stop turned violent, prompting a manhunt that involved a house to house search that lasted well into the night.

The lone suspect was eventually tracked down to a home in the San Francisco Bay-area community of Fremont, where he was involved in the standoff, Kelly said.

“We have one shooter that shot our officers,” Kelly told The Associated Press.

He said that earlier police were negotiating for the suspect to surrender. It was not immediately clear if that was still going on after the firing of the tear gas.

Kelly said that no one was home when the suspect broke in and barricaded himself inside.

No shots have been fired so far during the standoff and no one has been hurt, he said.

The incident started when an officer with a year’s service with the department stopped a white pickup truck in Fremont, which is about 40 miles south of San Francisco, police spokeswoman Geneva Bosques said.

The pickup truck backed up into the officer’s patrol car, a person in the truck fired shots that injured the officer and the shooter and another suspect fled on foot.

Shortly after that officers from several law enforcement agencies flooded the area and searching got underway.

A while later, a Fremont police officer with about 10 years of service with the department was wounded in a shootout with the suspect, officials said.

Bosques told the East Bay Times that the officer in the initial shooting was in critical condition after surgery. The second officer remained in stable condition.

Investigators had ordered residents of the blue-collar neighborhood to remain in their homes and to call police about anything suspicious. Police helicopters were deployed and police dogs used in searching yard-by-yard and door-to-door.

Kelly said residents of the neighborhood can breathe easier now that the shooting suspect has been confined to one site.

He said the others were with the suspect when the shooting erupted, but just the single gunman was accused in the violence.

Kelly said the Alameda County Sheriff’s Department has taken over tactical command of the scene while Fremont deals with its two fallen officers.