Democrats have secured control of both the US House of Representatives and Senate after defeating several Republican candidates in a major electoral upset, dealing a significant blow to President Donald Trump.

The victory gives Democrats the power to block Trump’s legislative agenda, investigate his administration over alleged corruption and challenge his policies during the final two years of his presidency.

The election results reportedly reflected growing public dissatisfaction with the rising cost of living, tariffs and Trump’s war against Iran, which has contributed to soaring fuel prices.

Democrats recorded major victories in traditionally Republican states, including Kansas, Iowa, Texas, South Carolina, North Carolina and Ohio.

In Kansas, Methodist minister Adam Hamilton defeated Republican incumbent Roger Marshall, becoming the first Democrat elected to represent the state in the Senate since 1932. In Iowa, Democrats also secured a Senate victory, marking their first win in the state since 2008.

In Texas, Democrat James Talarico defeated a Trump-backed Senate candidate, while Gina Hinojosa unseated Republican Governor Greg Abbott, ending decades of Republican control of the state’s top office.

Democrats also flipped several Republican-held House seats across Pennsylvania, New Jersey, Kentucky, Arizona and North Carolina.

Meanwhile, former Atlanta mayor Keisha Lance Bottoms reportedly made history as the first Black woman elected governor in the United States.

Despite the defeat, Trump told The New York Times that he was willing to accept the election results and work with Democrats. However, he later shared a picture of a red baseball cap bearing the word “VETO” on social media, signalling his intention to oppose Democratic legislation.

With their new majority, Democrats are expected to use their control of Congress to scrutinise Trump’s administration, investigate allegations surrounding his policies and block some of his appointments.

House Democratic leader Hakeem Jeffries described the outcome as a major setback for Trump’s MAGA movement.