Crimes committed on Walmart premises are not uncommon. On an average, a violent crime occurred at one of its stores at least once a day, an analysis conducted last year stated. In December, labor activists pressurized the mega-retailer to improve the security at its stores and parking lots across the U.S., reports said.

An incident which took place at a Walmart store in Shenzhen, China, on Sunday which left two people dead and nine others injured by a meat cleaver wielding man highlights the security lapses inside the retail company's stores.

A 30-year-old unemployed man suspected of being behind the incident was detained, police said adding that the motive for the attack was unknown, it was reported.

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In the U.S., violent crimes in Walmart stores are common. In January, a man was accused of using a motorcycle helmet to kill someone at a Walmart store in Tomball, Texas, and was charged with murder. Surveillance video from the store showed two people, Michael Brandon Jemison and Justin Jones arguing with each other, police said. Investigators said Jemison hit Jones with the helmet, causing him to collapse inside the store. The latter was taken to the hospital where he succumbed to his injuries, ABC 13 reported.

Over 200 violent crimes were reported last year including the ones such as shooting, stabbing, kidnapping, murder — all of which took place at Walmart stores across 4,500 locations in the U.S., according to an analysis of media reports published by Bloomberg Businessweek.

The stores have become hubs of criminal activities across the nation since 2000 when new CEO Leo Scott started slashing budgets, the report said.

In March 2016, a gunman killed a Walmart employee inside a North Texas store and then shot himself in an attempted suicide, a report said.

In June 2016, a SWAT team killed a hostage taker in Amarillo, Texas. Next month, three Walmart employees in Florida were charged with manslaughter after they chased and pinned down a shoplifter who died of asphyxia. In August, police discovered a meth lab inside a 6-foot-high drainage pipe under a Walmart parking lot in Amherst, New York, according to Bloomberg.

Police believed reduced staff numbers are to blame for the rise in crimes at Walmart stores. It now has 524 square feet of retail space for every one worker, which is a 19 per cent increase from 2006, the Bloomberg analysts said.

Scott, who introduced an aggressive cost-cutting crusade, led many stores to deteriorate.

"The constant calls from Walmart are just draining," Bill Ferguson, a police captain in Port Richey, Florida, told Bloomberg adding, "They recognize the problem and refuse to do anything about it."

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Another reason could be Walmart's decision of dropping its greeters who acted as a theft deterrent and replacing them by checkouts with customer-operated scanners. It brought more profits as, since 2006, sales per employee went up by 23 per cent to $236,804. However, crimes also increased during that time period, reports said.