By Todd Melby and Dan Riedlhuber

BLOOMINGTON, Minn./EDMONTON, Alberta (Reuters) - It was business as usual at Minnesota's Mall of America and Canada's West Edmonton Mall on Sunday, with most people either oblivious to any threat to attack the shopping centers or confident that the risk was too small to worry about.

Shoppers, employees and recreational "mall walkers" were out in full force despite news of a videotape attributed to al Shabaab, a Somali-based Islamist militant group behind a deadly 2013 attack on a Kenyan shopping center, that appeared to threaten the North American malls.

Mall of America (MOA), outside the Twin Cities, and West Edmonton Mall in Alberta issued statements saying they were implementing extra security measures but there were no signs of beefed-up law enforcement at either mall.

At the MOA, one of the largest in the country, hundreds of people turned out for a walk to support the National Eating Disorders Association. The event started before shops opened their doors

Among the participants were Tatum Pugrah, 23, and her boyfriend Nick Disbrowe, also 23. The couple said they were not aware of any special threat but were not entirely surprised when told about the videotape.

"If anyone is going to target anything, it's the Mall of America," Disbrowe said.

Clem Jauquet, 57, said he knew about the threat but was not concerned enough to skip his usual early-morning walk around the mall. “I trust the government will protect us from bomb threats,” he said.

The MOA, with 520 stores, a theme park and 50 restaurants, is in an area with one of the largest concentrations of Somalis in the United States. Minnesota's ethnic Somali population has mushroomed in the last two decades to more than 50,000.

U.S. authorities have been investigating the recruitment of ethnic Somali men into al Shabaab from the Minneapolis-St. Paul area since 2007.

An affiliate of al Qaeda, al Shabaab has been designated as a terrorist organization by the United States. It claimed responsibility for an attack at Nairobi's Westgate Mall that killed 67 people and fueled global concerns about mall safety.

West Edmonton Mall bills itself as the No. 1 tourist attraction in the oil-rich Canadian province of Alberta. It has more than 800 stores, two hotels and about 100 dining venues.

Hala Haddad, an employee at the mall, said the possibility of an attack would not keep her away from her job.

"I just don't think we should let other people influence our behavior going to shopping centers," she said.

(Writing By Frank McGurty; Editing by Tom Brown)