WASHINGTON — Tensions between the rich and poor are increasing and at their most intense level in nearly a quarter-century, a new survey shows. Americans now see more social conflict over wealth inequality than over the hot-button topics of immigration, race relations and age.

The survey released Wednesday by the Pew Research Center highlights U.S. perceptions of the economic divide, an issue that has moved to the forefront in the 2012 presidential campaign amid stubbornly high unemployment, increasing poverty and protests by the Occupy movement.

The findings come as voters in New Hampshire’s primary Tuesday night made clear that the economy was the issue that mattered most to them. In the end, they chose Mitt Romney by a large margin, even as Republican rivals already gearing up for more competitive contests in South Carolina and elsewhere had stepped up populist attacks on him as a heartless corporate raider who slashed jobs.

President Barack Obama has been promoting a campaign message of middle-class opportunity, calling for higher taxes on the very rich and successfully pushing a two-month extension of a payroll tax cut.

The Pew survey shows that younger adults, Democrats and African-Americans remained the most likely as in previous years to cite the existence of strong disagreements between rich and poor. But in the last two years, three important swing groups — whites, middle-income Americans and political independents — registered some of the biggest increases in those who now also hold this view.