Republican presidential nominee and former US President Donald Trump appeared to rule out seeking regime change in Iran, saying he wanted the country to succeed but it could not be permitted to have nuclear weapons.

“I would like to see Iran be very successful. The only thing is, they can't have a nuclear weapon,” Trump said in an interview with Iranian-American podcaster Patrick Bet-David on Thursday.

Asked if he would like to see Iran change its ruling system, Trump said: “We can't get totally involved in all that. We can't run ourselves, let's face it.”

During the interview Trump also highlighted that he pressured China to stop buying oil from Iran during his presidency by threatening to block its access to US markets, a move he said was effective. When asked if he would revive the strategy, Trump said, "Different strategies. It all depends."

Last month, Trump told reporters that Washington must come to an agreement with Iran, in a seeming departure from his hardline stance toward its main adversary in the Middle East.

Trump's withdrawal from the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), in 2018, marked the beginning of what he termed 'maximum pressure' sanctions on Tehran.

The policy was praised by the group Iranians for Trump, who say that a Trump presidency could be an effective approach to advancing freedom and democracy in Iran.

Trump has repeatedly expressed his preference for deals with Washington's opponents but his comments come as tensions in the Mideast have ramped up and his campaign said Iran has made threats on his life.