Law enforcement agencies are investigating a series of hoax bomb threats that targeted major US retailers and grocery stores in an apparent extortion scheme for thousands of dollars in gift cards, bitcoin and cash, according to a report. Kroger, Meijer, Walmart and Whole Foods are among the companies that have been targeted in several states, according toThe Wall Street Journal. Callers have threatened to detonate bombs if gift cards, bitcoin or other payments are not provided, the newspaper reported. The FBI is working with state and local law enforcement to identify the threats, which have so far been unfounded, WSJ reported. It is unclear whether the calls are part of an organised effort. Callers have used block numbers to conceal their identities, according to police. One call to a Whole Foods in suburban Chicago reportedly demanded $5,000 in bitcoin and threatened to detonate a pipe bomb. Another call to a Kroger in New Mexico reportedly demanded an employee wire money and threatened that a bomb would go off if they called the police. Calls to a Meijer grocery store in Wisconsin demanded $5,000 in Apple gift cards. The threats echo similar menacing calls that have been a mainstay of local news outlets across the US in the past several years. After such threats, law enforcement agencies are typically called to the scene to evacuate the stores, causing major headaches for retailers and surrounding traffic. The latest efforts are “another evolving scam” for US retailers, according to Lisa Bruno, a senior executive vice president of retail operations at the Retail Industry Leaders Association, speaking to The Wall Street Journal. The threats also appear to be separate from those made towards retailers like Target, where stores in at least five states have faced threats over the company’s support for LGBT+ shoppers during Pride Month. Read More Pride collection backlash has derailed retailers, but LGBT designers are more empowered than ever Starbucks workers at 150 stores to strike over alleged ban on Pride decor