Democratic presidential candidate Kamala Harris said in her Democratic National Convention speech on Thursday that as president she will aim to pass a middle-class tax cut.

Harris said her opponent, Republican presidential candidate Donald Trump, was not concerned about the middle class.

"Instead of the Trump tax hike we will pass a middle-class tax cut that will benefit more than 100 million Americans," Harris said in her speech, without giving further details.

Harris argued that the Republican former president's plan for tariffs will serve as a price hike.

Trump has threatened to use tariffs to achieve what he terms as fair trade relations and deals with other countries.

Harris called building the middle class "a defining goal of her presidency" and vowed, if elected, to create an "opportunity economy" where "everyone has the chance to compete and a chance to succeed."

Last week, Harris outlined proposals to cut taxes for most Americans, ban "price gouging" by grocers and build more affordable housing.

Her agenda may run into resistance from both corporations and the U.S. Congress, which rejected similar proposals when they came from Democratic U.S. President Joe Biden.

Harris is aiming to draw a contrast with her opponent on broad economic policies, specifically on tariffs and taxes.