Sen. Bernie Sanders was on hand at Walmart's annual shareholder meeting as the retailer's CEO said Congress should hike the federal minimum wage.

Chief Executive Doug McMillon told shareholders at his company's annual meeting that $7.25 an hour "is too low."

Walmart raised its starting wage to $11 an hour in early 2018 and this began giving U.S. hourly workers paid time off.

Walmart CEO Doug McMillon is adding his voice to those calling for an increase in the federal minimum wage. Addressing an audience of shareholders and presidential candidate Bernie Sanders at the retailer's annual meeting Wednesday, McMillon fended off the Vermont senator's accusation that his company pays "starvation wages."

Over the past four years, Walmart "invested an incremental $4.5 billion in pay, beyond our traditional annual wage increases, for our U.S. store and club associates," said McMillon, who added of the federal minimum, unchanged since 2009: "$7.25 is too low."

With McMillon at the helm, Walmart raised its starting wage to $11 an hour at the beginning of 2018 and earlier this year began giving U.S. hourly workers paid time off, but has not budged on calls from Sanders and others that it match Amazon's $15 an hour minimum. Amazon in October 2018 hiked its minimum hourly pay to $15, with CEO Jeff Bezos declaring "we listened to our critics."

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"It's clear by our actions and those of other companies that the federal minimum wage is lagging behind," said McMillon, who called on Congress to increase the federal minimum. "Any plan should take into account phasing and cost of living differences to avoid unintended consequences," he added.

About 1.5 million Americans are employed by Walmart, making it the nation's biggest private employer.

CEO of Walmart since 2014, McMillon received almost $24 million in cash and stock-based pay over the last year, a compensation package blasted by Sanders as more than 1,000 times greater than what the average Walmart worker makes.

Sanders attended the meeting to urge Walmart to pay its employees "a living wage of $15 an hour" and to give an hourly worker a seat on its board, pitching the idea on behalf Cat Davis, a Walmart employee who filed the proposition, according to United for Respect, a group that advocates for workers.

McDonald's — another frequent target of Sanders — in March said it no longer will take part in lobbying against minimum wage hikes at the local, state or federal level.