US president Donald Trump said on Saturday his planned meeting with North Korean leader Kim Jong Un could fizzle without an agreement or it could be “the greatest deal for the world” to ease nuclear tensions between the two countries.

“I may leave fast” if progress does not seem possible, Mr Trump said at a campaign rally for Republican congressional candidate Rick Saccone in western Pennsylvania. Mr Trump said he believes North Korea wants to make peace and that, “I think it’s time.”

A time and place to meet has not yet been set, although the meeting is supposed to happen by the end of May.

“Who knows what’s going to happen?” said Mr Trump, who added that if the meeting takes place, “I may leave fast or we may sit down and make the greatest deal for the world.”

Mr Trump made the shocking decision on Thursday to meet with Kim after the North Korean leader’s invitation was relayed by a South Korean delegation who visited the White House. The move abruptly reversed decades of US policy aimed at preventing North Korea from developing nuclear weapons and ballistic missiles.

During his speech in Pennsylvania, Mr Trump also attacked his critics and raised the idea of having drug dealers face the death penalty during a raucous rally on Saturday for a Republican congressional candidate.

Mr Trump’s appearance was aimed at helping Mr Saccone in a district Mr Trump won overwhelmingly in 2016 as part of a narrow win in Pennsylvania.

But although he heartily endorsed Mr Saccone as a “really good person,” mr Trump spent a lot of time talking about his own fortunes in a “Make America Great Again” rally in an airport hangar at the Pittsburgh International Airport.

He said it was crucial for Republicans to muster forces to turn back a strong Democratic drive to win one or both houses of the US Congress in November midterm elections.

“We need Republicans. We need the vote,” Mr Trump said, saying Democrats would take away, among other things, “your Second Amendment rights” to bear firearms.

Mr Trump said the country should discuss having drug dealers face the death penalty because they are responsible for thousands of deaths. “I don’t know if that’s popular. I don’t know if that’s unpopular.”

Continuing his battle against the mainstream news media, Mr Trump insulted NBC News’ “Meet the Press” host Chuck Todd and Democratic congresswoman Maxine Waters.

Under pressure over a scandal involving a porn star named Stormy Daniels, Mr Trump singled out his wife, Melania, for praise.

“You think her life is so easy folks? Not so easy,” he said.

A day after getting news that the US economy produced 313,000 jobs last month, Mr Trump said his policies are paying off. He said 25 per cent tariffs on steel imports will boost Pennsylvania’s economy.

“Your steel is coming back. It’s all coming back,” Mr Trump told several thousand cheering supporters.

The president vowed to fight any retaliatory trade measures by, for example, slapping taxes on imported European cars.

Critics say the tariffs could trigger retaliatory trade measures and damage the US economy.

Mr Trump also said he hoped to run for reelection against Democrat Oprah Winfrey, although the entertainer has ruled out a run. “I’d love to beat Oprah. I know her weakness,” said Trump.

Mr Saccone is trying to win an election on Tuesday in Pennsylvania’s 18th District to replace Republican Tim Murphy, who resigned last fall while enmeshed in a sex scandal.–Reuters