San Diego police are trying to flush a gunman out of an apartment block in a siege that has diverted incoming flights.

Officers stormed the building and exchanged gunfire with the man after responding to a domestic violence call on Wednesday morning.

Police say the man, reportedly armed with a high-powered rifle, has been firing sporadically from his rooftop home. 

No one has been reported hurt so far during the standoff in the upmarket Bankers Hill neighbourhood.

It's not clear if anyone is inside the apartment besides the suspect.

Police told residents on Twitter: "Stay away from all windows until further notice and Shelter in place."

Officers were using tear gas in a bid to drive out the suspect, according to local media in the southern California city.

Flights have been barred from landing at San Diego airport due to the standoff, says the Federal Aviation Administration.

FAA spokesman Ian Gregor said flight departures were being allowed at the air hub, directly west of the standoff.

SWAT officers have poured into the area, sealing off streets as they surrounded the gunman.

Witnesses said they had heard multiple gunshots at the scene on Brandt Street.

Two nearby schools have been placed on lockdown as a precaution, said police.