WASHINGTON, United States – Donald Trump faced a radically transformed and hostile political landscape on Wednesday after US voters handed control of Congress to the Democrats in a stunning rebuke to his presidency.

The result was a personal humiliation for the 80-year-old Trump as a Democratic wave swept into his Republican heartland, boosted by anger at soaring energy costs and his costly, dragging war with Iran.

The Democratic capture of both the Senate and the House of Representatives signals an end to Trump's stranglehold on US politics and gives Democrats the power to block legislation, launch investigations into Trump's administration and thwart his appointments.

The results reflected deep frustration over the cost of living, tariffs and Trump's war with Iran, which has sent fuel prices soaring and compounded dissatisfaction with an already deeply unpopular president.

"This is so incredibly exciting. We can get our country back," Kathy Jackoway said in Texas, celebrating a win by Democratic Senate candidate James Talarico.

Trump struck a conciliatory tone despite his history of rejecting election defeats, telling The New York Times he was "absolutely willing" to accept the results.

"I think the Democrats did a good job," the 80-year-old told Fox News, in rare praise for his political opponents. "They fought hard."

But he sought to distance himself from his party's poor showing, adding: "I don't view it as a hit on me."

He acknowledged that the Iran conflict had contributed to the result but defended the military campaign, and he suggested the rival parties could find common ground on immigration.

- Republican heartland -

Democrats flipped seats that had long been held by Republicans, scoring breakthroughs in South Carolina, North Carolina, Iowa, Kansas, Ohio, Texas and Maine.

In Maine, former logger Troy Jackson defeated longtime Republican Senator Susan Collins.

In Kansas, Methodist minister Adam Hamilton became the first Democrat elected to the Senate from the reliably conservative state since 1932.

Iowa had not elected a Democratic senator since 2008.

In Texas, Democrats won not only a Senate seat but also the governor's race, ending decades of Republican rule.

Democrats protected key Senate seats of their own, including Jon Ossoff in Georgia and an open seat in New Hampshire.

In Michigan, Abdul El-Sayed defeated former Republican lawmaker Mike Rogers, making him the first Muslim elected to the upper chamber of Congress.

El-Sayed won despite a last-minute curveball when congresswoman Haley Stevens, who lost the Democratic primary to El-Sayed, came out in support of Rogers.

In the House, Democrats made gains in Pennsylvania, Kentucky, Arizona, North Carolina, Wisconsin and New Jersey, including districts Trump had carried comfortably in 2024.

Democrats also won Georgia's governorship, electing former Atlanta mayor Keisha Lance Bottoms as the first Black woman governor in US history.

Republicans had some consolation in Florida, where Trump-backed Byron Donalds became the state's first Black governor and Ashley Moody retained a Senate seat.

But the night was "a big wipeout and a strong repudiation of Donald Trump and his policies," George Washington University professor Todd Belt told AFP.

- Trump on defensive -

House Democratic leader Hakeem Jeffries declared Trump's MAGA movement "on the run."

Jeffries could become the first Black speaker of the House when the new Congress convenes in January.

Trump insisted on social media that Republicans would have won "IN A LANDSLIDE" if he had been running, though he had repeatedly urged supporters throughout the campaign to "pretend I'm on the ballot."

He also repeated his threat to use the presidential veto on Democrat-passed bills, posting a picture on social media of a red baseball cap reading just: "VETO."

On the international front, Russia said it hoped Trump will continue his "peacemaking efforts" and China said it would "continue working" with the United States.

Iran's supreme leader Mojtaba Khamenei said he did not expect the election results to bring about a shift in US policy.