Iran on Monday named Mojtaba Khamenei to succeed ​his father Ali Khamenei as Supreme Leader, signaling that hardliners remain firmly in charge in Tehran a week into its conflict ‌with the United States and Israel, reported Reuters.

Mojtaba, a mid-ranking cleric with influence inside Iran's security forces and vast business networks under his father, had been seen as a frontrunner in the lead up to the vote by the assembly, a body of 88 clerics charged with choosing the new leader after Ali Khamenei.

"By a decisive vote, the Assembly of ​Experts, appointed Ayatollah Seyyed Mojtaba Hosseini Khamenei as the third Leader of the sacred system of the Islamic Republic of Iran," the ​assembly said in a statement issued just after midnight Tehran time.

The position gives Mojtaba the final say in all ⁠matters of state in the Islamic Republic.

Mojtaba’s appointment will likely draw the ire of US President Donald Trump, who said on Sunday that Washington should ​have a say in the selection. "If he doesn't get approval from us, he's not going to last long," he told ABC News. Israel, ahead of the ​announcement, threatened to target whoever was chosen.

Mojtaba's father, Supreme Leader Ali Khamenei, was killed in one of the first strikes launched against Iran more than a week ago.

Meanwhile, the US military on Sunday reported a seventh American has died from wounds sustained during Iran's initial counter-attack a week ago, a day after Trump presided over the return to the ​United States of the remains of the six others who died.