Senator Bernie Sanders spoke at the New Hampshire AFL-CIO Labor Day breakfast in Manchester. Cheryl Senter for The Boston Globe

MANCHESTER, N.H. — Returning to the state that helped launch him into the national spotlight, US Senator Bernie Sanders on Monday stepped up his criticism of Amazon owner Jeff Bezos, reprising the income inequality themes that fueled his 2016 presidential run.

Sanders, speaking at the annual AFL-CIO New Hampshire breakfast, continued his feud with the business titan, saying Bezos is growing richer while many of his employees struggle.

“I am uncomfortable when one person, wealthiest-guy-in-the-world Jeff Bezos, watches his wealth increase today by $250 million,” the Vermont senator told about 350 of the state’s political and labor union elite. “But there are thousands of workers who are employed by him that are earning wages so low they are on food stamps, Medicaid, and subsidized housing.

“So today,’’ he added, “we say to the Bezoses, and today we say to the owners of Walmart, the Walton family, today we say to all the billionaires running large multinational corporations: We are not going to subsidize you anymore; pay your workers a living wage.”

While Amazon ignores most attacks President Trump has leveled at the company, it took the unusual step of responding to Sanders last week, calling his claims “inaccurate and misleading.”

While it is notable when a potential presidential candidate speaks at a political event in a state that holds the nation’s first presidential primary, this was actually the fifth consecutive year Sanders headlined this particular Labor Day event. After his appearance, he took off for a pair of events in Vermont, where he is seeking reelection this year.

But his speech diverged from the hundreds he has given in New Hampshire in three ways: He reduced his typical stump speech from an hour to 20 minutes; he discussed gun control measures; and he mentioned the nation’s “struggles” with racial discrimination.

“Our job is to say and to understand that this country from its inception has struggled with the issue of discrimination,” said Sanders, who was often accused of not discussing race matters enough as a presidential candidate. “We have struggled with it not only for African-Americans, not only Latinos, not only Asians, not only Italians, not only Irish, not only the Jews.”

Sanders also addressed efforts to reduce gun violence. The issue is on the minds of Democratic voters this year and his 2016 opponent, Hillary Clinton, often criticized Sanders for some votes, particularly one that protected gun manufacturers from being sued in cases of death resulting from guns.

On Monday, Sanders noted that Vermont and New Hampshire are rural states where residents hunt, but said it was time “for common-sense gun laws.”

Sanders offered no clues as to whether he may run again for president in 2020. In fact, when it came explicitly to politics, Sanders failed to endorse his son, Levi, who is running in a New Hampshire congressional race and has a primary next week. Instead, in his opening remarks, Sanders pointed out his son and asked him to stand for the crowd.

Indeed, the future of Sanders politically is one of the biggest questions in the state. Despite the fact that Sanders won the 2016 New Hampshire primary by 23 percentage points, recent polls show him only among the front-runners, including US Senator Elizabeth Warren of Massachusetts and former Vice President Joe Biden.

A University of New Hampshire Survey Center poll two weeks ago showed Sanders leading a 13-person field with 30 percent support, with Biden at 19 percent and Warren with 17 percent.

Some local Sanders aides argue that should he run again, he has huge advantages like a ready-to-go network of former supporters to build on.

The reality, however, might be more complicated. As Levi Sanders runs in an 11-way Democratic primary, former Bernie supporters are split among a number of candidates.

“To be honest, I think a number of Bernie supporters are open-minded when it comes to the many progressives thinking about running in 2020,” said former New Hampshire state senator Burt Cohen, who served on Sanders’ 2016 steering committee.

Still, Sanders noted Monday that in the years he has been addressing this same group he has helped move the nation politically to the left. He said when he crisscrossed the state three years ago calling for “Medicare for all,” it was considered a “radical idea,” and now he said “70 percent of Americans think it is a good idea.”