Mohammad Reza Aref

Iranian President Masoud Pezeshkian has announced the commencement of efforts to relocate the country's capital from Tehran to the southern borders, along the shores of the Persian Gulf.

Israel's foes vowed revenge on Saturday after Iran-backed Lebanese militant group Hezbollah announced its longtime leader Hassan Nasrallah was killed in an Israeli air strike on Beirut suburbs.

World powers also warned of the killing's potential repercussions, with the spectre of all-out war looming over the Middle East.

Hundreds of people gathered at a mosque in Qatar on Friday to farewell slain Hamas leader Ismail Haniyeh after his killing in Tehran, an attack blamed on Israel that deepened fears of a regional war.

Haniyeh, the Palestinian armed group's political chief, played a key role in mediated talks aimed at ending nearly 10 months of war between Hamas and Israel in Gaza.

Iran's reformist former president Mohammad Khatami has skirted a media ban to endorse moderate incumbent Hassan Rouhani for a second term over conservative challengers in a May 19 election.

Iranian moderates and reformists who support last year's landmark nuclear deal have won the largest number of seats in parliament following runoff elections, marking a shift away from hard-liners and boosting moderate President Hassan Rouhani as he looks to secure a second term in office.