US President Donald Trump said Sunday that a "great dislike" for Israel, public opposition to the war with Iran and rising gasoline prices were the primary reasons Republicans suffered sweeping losses in last week's midterm elections.

In an interview with CBS News' 60 Minutes, Trump acknowledged that the war had hurt Republicans politically, particularly as gasoline prices increased.

"They didn't like the war. They didn't like the fact that gasoline went up," he said.

"There's a great dislike, incredibly, for Israel. There seems to be a dislike for Israel. So you have that, you have the war itself, you have the gas prices, and I think those are the primary reasons," he added.

Despite acknowledging the war's political costs, Trump defended his decision to attack Iran, saying he would make the same choice again.

"My answer is an emphatic yes because you can't let Iran have a nuclear weapon," he said.

Trump claimed the US had won the war and that Tehran was interested in reaching an agreement.

"We would have had a deal except for this election," he said, suggesting the Democratic victory had complicated negotiations.

Asked whether he intended to escalate the conflict following the elections, Trump said he was not seeking further escalation.

"I'm not looking to. I don't think there's any reason to," he said.

He also repeated his claim that Israel would not exist without US military strikes against Iran's nuclear facilities.

Democrats secured control of both the House of Representatives and the Senate in Tuesday's elections, dealing a major setback to Trump's administration. (AA)