Hours after Iran's Supreme Leader Ayatollah Ali Khamenei warned that the US will "suffer irreparable harm" for interfering in its conflict with Israel, Donald Trump has responded, saying he might strike Iran or he might not.

Addressing a press conference from the White House's south lawn, Trump spoke about whether the US will join Israel in its military offensive against Iran to ensure Tehran does not develop a nuclear weapon.

"I may do it, I may not do it - nobody knows what I'm going to do," he said.

This comes after Iran's Supreme Leader had said that his country "will never surrender" in response to Donald Trump's call for an "unconditional surrender" from Tehran's regime.

"The US President threatens us. With his absurd rhetoric, he demands that the Iranian people surrender to him. They should make threats against those who are afraid of being threatened. The Iranian nation isn't frightened by such threats," he said.

On Tuesday, Trump issued a warning to Iran's Supreme Leader, asking him to 'surrender unconditionally' and also stating that he knows where Ayatollah Ali Khamenei is hiding and can get him eliminated.

"We know exactly where the so-called 'Supreme Leader' is hiding. He is an easy target, but is safe there - We are not going to take him out (kill!), at least not for now," Trump wrote on Truth Social.

Trump said the only reason the US is choosing not to eliminate Khamenei is to avoid any retaliation against American civilians and troops.

"But we don’t want missiles shot at civilians, or American soldiers. Our patience is wearing thin. Thank you for your attention to this matter!" the US President said.

Meanwhile, the Israel Defence Forces (IDF) has said that Iran has fired a barrage of missiles at Israeli cities, "targeting civilians for the sixth consecutive day".

Sirens were heard across most of Israel on Wednesday evening, alerting residents to rush into bunkers till further notice.