RICHMOND -- Two people were injured in a shooting at a busy parking lot outside a Target store Tuesday evening, police said.

At 5:43 p.m., police received multiple 911 calls reporting shots fired in a parking lot outside a Target store on Macdonald Avenue near 42nd Street, Richmond police Sgt. Nicole Abetkov said.

Officers in the vicinity also heard shots fired and responded to the area, but the victims and suspects were gone before officers arrived, Abetkov said.

A short time later, Doctors Medical Center in San Pablo notified Richmond police that two males had arrived at the hospital with gunshot wounds, Abetkov said.

One of the victims is in critical condition and was transported by air to John Muir Medical Center in Walnut Creek, according to Abetkov.

The second victim suffered a gunshot wound that is not considered life-threatening. He was transported via ambulance to John Muir Medical Center.

Both victims are described as males estimated to be in their late teens to early 20s, Abetkov sad.

She said that because of the early evening hour, the parking lot was likely to have been "pretty populated at the time."

Detectives are following up with witnesses who may have information and are searching surveillance video for footage of the suspects, Abetkov said.

The motive for the shooting remains under investigation.

Anyone with information may contact Richmond police at 510-232-1214 or may do so anonymously at 510-232-TIPS.