A police suspect hijacked his vehicle, got out of the car and ran to the store on Hyperion Avenue in the Silver Lake neighborhood, LOPD Officer Mike Lopez told CNN.
Lopez said customers have disappeared from the trader Joe's. Police are still trying to determine if there are hostages in the store.
Los Angeles Fire Department spokeswoman Margaret Stewart said a 20-year-old patient had been illegally hospitalized. She was removed from a vehicle, not inside the store, Stewart said.
"We are on standby and ready to assist, but no confirmation of how many patients can be in it," added Stewart.
Earlier, the LAPD tweeted, "There is an active police incident at Trader Joe's near the junction of Hyperion Ave and Griffith Park Blvd in #Silberlake. Please stay away from the area."
The incident started around 1
An aerial photo shot from a helicopter showed an armored vehicle parked in front of the front doors, armed officers carrying shields, and a man walking outside with his hands raised.
The video also featured officers carrying a person who appeared to have been injured, as well as people climbing out of a shop window and climbing down a rope ladder.
Lopez said he did not know if there were any shots from the police or suspects.
This is an evolving story.