Mr. Schlademan said Wal-Mart employees had walked off the job in Dallas, Seattle, Miami, Sacramento and Orlando, Fla., and in the Chicago and Washington areas. Tuesday’s job actions were sponsored by the Organization United for Respect at Walmart, or OUR Walmart, a group of several thousand Walmart employees that is closely affiliated with the United Food and Commercial Workers Union.

“These leaders of OUR Walmart have engaged in a strike to protest Wal-Mart’s retaliation and to send a message to Wal-Mart and their co-workers that they have a right to speak out,” Mr. Schlademan said. “The idea that this is just a publicity stunt is inaccurate.”

He said this week’s events were aimed at pressing Wal-Mart to increase wages, stop cutting workers’ hours and treat employees with respect.

Mr. Tovar said: “We have some of the best jobs in retail. Our full-time average wage is $12.54 an hour, which is $5 above the federal minimum wage.” He said that 300,000 Wal-Mart employees had worked at the company for more than 10 years and that Wal-Mart’s turnover rate was lower than the industry average.

Mr. Tovar said those statistics showed that those who participated in the job action were not representative of Wal-Mart’s 1.4 million employees nationwide.

“It’s no secret that the unions want to organize our associates,” he said. “These protests are union-led and union-funded by unions that are trying to further their own political and financial agenda.”

Julius G. Getman, a labor expert at the University of Texas School of Law, said it can be hard to draw a line between what is a strike and what is publicity. He said the union and OUR Walmart were searching for ways to get Wal-Mart to improve wages and conditions when they see how hard it would be to unionize even a handful of Walmart stores.

“Wal-Mart has so much power — unions typically don’t win those kind of drives,” he said. “They’re groping, they’re planning to find a way to take on Goliath.”