Black Friday was marred at two California stores after one shopper pepper-sprayed another person during jostling in an Xbox aisle and one shopper was shot in an apparent parking lot robbery attempt.

Update at 1:37 p.m. ET: WITN-TV in eastern North Carolina quotes Kinston Sgt. Roland Davis as saying an off-duty officer working as a security guard for Walmart on Black Friday used pepper spray to try to quell a disturbance. One person was arrested, WITN reports.

Update at 11:36 a.m. ET: KGO-TV says the shooting occurred outside a Walmart in San Leandro. The TV station quotes police as saying it was a "robbery gone wrong." The victim was hospitalized in critical condition. KGO says a family member detained one suspect but a second one fled.

Police say the victim was coming out of the San Leandro store around 1:45 a.m. with family members when they were confronted by two men who demanded their purchases, the Associated Press reports. When the family refused, a fight broke out, and the gunman fired a single shot.

Officers patrolling near the parking lot went to the center lot aisle near the front of the store where they found a victim suffering from a gunshot wound and the victim's family members detaining a possible suspect, police said.

It appears the victims were walking to their car when multiple suspects confronted them, police said.

After suspects asked the victims for their items and were refused, a fight ensued. One suspect pulled a gun and shot one of the victims.

The victim was taken to a hospital in critical but stable condition, police said.

Family members wrestled down one of the suspects as another fled.

Once officers arrived, the detained suspect -- a man in his mid-20s -- was arrested, police said.

It is unknown whether the arrested man was the gunman in the incident.

The Hesperian Boulevard Walmart listed its doors opening Thursday night at 10 p.m. for early Black Friday shopping and deals.

San Leandro police Sgt. Mike Sobek told reporters at the scene this morning that the shooting was a "robbery gone bad."

Walmart parking lot entrances were reportedly blocked by numerous police cars at 4 a.m. after the shooting, a clerk said from the Big 5 Sporting Goods across the street.

Police said investigators are still at the scene this morning.

Update at 10:03 a.m. ET: KNBC quotes one witness as saying the incident began as shoppers waited in line for the new Xbox 360. The witness told the Los Angeles TV station that a woman, who had two children with her, got upset with the way people were pushing in line, pulled out pepper spray and used it on other shoppers. KNBC says no one had been arrested, and authorities were reviewing surveillance video.

Original posting: At least 20 people sustained minor injuries after a Black Friday shopper at a California Walmart attacked fellow shoppers with pepper spray during a shoving match in the video games aisle, according to KTLA-TV.

The Los Angeles Times quotes Fire Capt. James Carson as saying the woman, who is being sought, used the spray more than once "to gain preferred access to a variety of locations in the store."

Read: Update on Black Friday.

One customer, Alejandra Seminario, 24, told the Times one incident occurred when shoppers apparently began grabbing at video games five minutes before the 10 p.m. Black Friday kickoff.

"People started screaming, pulling and pushing each other, and then the whole area filled up with pepper spray," Seminario said.

In Fayetteville, N.C., police are looking for two suspects after gunfire erupted early Friday at Cross Creek Mall, the Associated Press reports.