One dead in LA supermarket siege

A gunman who holed up in an Los Angeles supermarket after allegedly shooting his grandmother and girlfriend has been arrested, leaving the Trader Joe's store in handcuffs.

One woman was killed inside the supermarket, Los Angeles Mayor Eric Garcetti said.

Police at the scene said a number of people inside the store were held against their will for three hours on Saturday afternoon.

Officers with riot gear, armed with rifles, stood along the side of the Trader Joe's in the Silver Lake area on Saturday afternoon and used mirrors to try to look inside as hostages periodically came out the front door with the hands raised.

The suspect walked out with a cluster of four hostages and appeared to be already handcuffed as the group emerged through the front door.

Police immediately surrounded the suspect, searched him and then brought him to a waiting ambulance. The man appeared to have blood on his left arm.

Investigators believe the suspect, whose name hasn't been released, had shot his grandmother and girlfriend around 1.30pm in South Los Angeles and then fled in a 2015 Toyota Camry.

Officers spotted the suspect's car near Hollywood and tried to pull him over, but the man refused to stop and led officers on a pursuit, he said.

During the chase, the suspect shot "multiple rounds" at officers, though no officers were struck by the gunfire, he said.

At least one officer is believed to have returned fire, Montgomery said.

The suspect eventually crashed his car outside of the Trader Joe's supermarket and then ran into the store.

Don Kohles (91) was walking into the supermarket when he saw a car being chased police crash into a pole just outside.

Police fired at the driver, shattering the store's glass doors and Kohles and others inside took cover and laid on the floor as the suspect ran into the store, he said.

People frantically tried to flee from the store and some were seen climbing through windows, jumping down and others darted through the back door

President Donald Trump tweeted that he is "Watching Los Angeles possible hostage situation very closely" and that Los Angeles police officers were working with federal law enforcement.