NEW YORK >> Walmart confirmed Thursday that it is closing 10 percent of its Sam’s Club warehouse stores — a move that a union-backed group estimated could cost thousands of jobs — on the same day the company announced that it was boosting its starting salary for U.S. workers to $11 an hour and handing out bonuses.

The world’s largest private employer said it was closing 63 of its 660 Sam’s Clubs (but none in Hawaii) over the next few weeks, with some shut already. Up to 12 are being converted into distribution centers to handle online orders, the company said late Thursday.

It did not disclose how many people would lose their jobs, but said some workers may be placed at other Walmart locations. Making Change at Walmart, a campaign backed by the United Food and Commercial Workers International Union, estimates that 150 to 160 people work at each Sam’s Club store, meaning the closures could affect about 10,000 people.

On Twitter, Sam’s Club responded to people’s queries by saying, “After a thorough review of our existing portfolio, we’ve decided to close a series of clubs and better align our locations with our strategy.”

News reports said Sam’s Clubs stores were closing in Texas, California, New Jersey, Ohio, Indiana and Alaska, among other states.

Earlier in the day, Walmart had cited the sweeping Republican tax overhaul that will save it money in announcing the higher hourly wages, one-time bonuses and expanded parental benefits that will affect more than a million hourly workers in the U.S. Employees previously started at $9 an hour, with a bump up to $10 after completing a training program.

The company said the wage increase benefits all hourly U.S. workers at its stores, including Sam’s Club, as well as hourly employees at its websites, distribution centers and its Bentonville, Ark., headquarters. A one-time bonus will be given to those Walmart employees who won’t receive a pay raise. The amount, between $200 and $1,000, depends on how long they have worked at the company.