NEW YORK — Unions lent their muscle to the long-running protest against Wall Street and economic inequality Wednesday, fueling speculation about how long the camp-out in lower Manhattan — and related demonstrations around the country — will continue.

Thousands of protesters, including many in union T-shirts, filled lower Manhattan’s Foley Square on Wednesday and then marched to Zuccotti Park, where the protesters have been camping since Sept. 17. Labor leaders say they will continue to support the protests, both with manpower and donations of goods and services.

“The great thing about Occupy Wall Street is that they have brought the focus of the entire country on the middle class majority,” said George Aldro, 62, a member of Local 2325 of the United Auto Workers, as he carried the union’s blue flag over his shoulder through lower Manhattan.

“We’re in it together, and we’re in it for the long haul.”

The protesters have varied causes but have spoken largely about unemployment and economic inequality, reserving most of their criticism for Wall Street. “We are the 99 percent,” they chanted, contrasting themselves with the wealthiest 1 percent of Americans.

The unions were donating food, blankets and office space to the protesters, said Dan Cantor, head of the Working Families Party. But he said the young protesters would continue to head their own efforts.

The Occupy Wall Street protests started Sept. 17 with a few dozen demonstrators who tried to pitch tents in front of the New York Stock Exchange. Since then, hundreds have set up camp nearby in Zuccotti Park and have become increasingly organized.