Thousands of Iranians have taken to the streets to mourn the death of General Qassem Soleimani who was the head of the Iranian Islamic Revolutionary Guard Corps' (IRGC) Quds Force.

Iran's Supreme Leader Ayatollah Ali Khamenei paid tribute to him and called him a "martyr" before promising "harsh revenge".

Iranian President Hassan Rouhani echoed the threat of revenge and promised that there will be consequences. Foreign Affairs Minister Javad Zarif condemned the killing as an "act of state terrorism".

IRGC officials, religious leaders, ministers, members of parliament, and the business community reacted in unison and hailed the commander as a fallen hero.

The White House and Pentagon said the attack on Soleimani was carried out with the aim of deterring future attacks allegedly being planned by Iran.

The Pentagon said Trump had ordered Soleimani's "killing" after pro-Iran protesters this week stormed the US embassy in Baghdad.