Iran will fight on and keep the Strait of Hormuz shut as leverage against the United States and Israel, new Supreme Leader Mojtaba Khamenei said on Thursday in defiant first comments attributed to him since he ​succeeded his slain father.

Hours later, Israeli Prime Minister Benjamin Netanyahu used his first press conference since the start of the war to make his own strong statement, issuing a veiled threat to kill Khamenei and defending the ‌military assault on Iran, which has claimed thousands of lives and shaken energy and stock markets.

"I wouldn’t issue life insurance policies on any of the leaders of the terrorist organization ... I don't intend to give an exact message here about what we are planning or what we are going to do," Netanyahu said, standing between two Israeli flags and taking questions via video link.

In Iran, Khamenei did not appear in person and his remarks were read out by a state television presenter. No images have been released of him since an Israeli strike at the start of the war that killed much of his family, including his ​father and wife.