FISHERSVILLE, Va. (AP) — Republican presidential candidate Mitt Romney is claiming that President Barack Obama would raise taxes on middle-income Americans.

Romney on Thursday said middle-class families would pay $4,000 more each year in taxes under Obama’s plan. The Republican candidate is relying on a study from a conservative think tank that’s also referenced in one of his campaign ads.

Obama’s campaign disputes the claim, calling the figure, quote, “a partisan distortion” of the American Enterprise Institute study.

Romney appeared with running mate Paul Ryan at a rally in Fishersville, Va.