By Parisa Hafezi and Angus McDowall DUBAI, March 8 (Reuters) - Iran's new supreme leader faces a massive external assault and growing internal anger at a time when the backing of the diehard ideologues who supported his predecessors is less clear than before.

Mojtaba Khamenei, the son of Iran's Ayatollah Ali Khamenei, who was killed in US-Israeli strikes, has been chosen as his successor.

The new leader of the Islamic regime will be Khamenei’s son Mojtaba. President Trump has called him an “unacceptable” option.

Iran on Monday named Mojtaba Khamenei to succeed his father, Ali Khamenei, as supreme leader, signalling that hardliners remain firmly in charge in Tehran more than a week ‌into its conflict with the United States and Israel.

Ayatollah Ali Khamenei was killed by US and Israeli strikes a week ago and his hardline son Mojtaba Khamenei is seen as a frontrunner to succeed him