General Soleimani was widely seen as the second most powerful figure in Iran, behind Supreme Leader Ayatollah Ali Khamenei.
The 62-year-old spearheaded Iran’s Middle East operations as head of the elite Quds Force, and was hailed as a heroic national figure.
But the US branded the commander and the Quds Force terrorists, holding them responsible for the deaths of hundreds of US personnel.
Speaking on Friday afternoon, President Trump said Soleimani was “plotting imminent and sinister attacks” on US diplomats and military personnel in Iraq and elsewhere in the region.
Soleimani was seen as the second most powerful figure in Iran.
The general was killed by an air strike at Baghdad airport early on Friday, on the orders of President Trump. The president said the action was taken to stop, not start, a war.
Iran’s Ayatollah Khamenei said “severe revenge awaits the criminals” behind the US attack. Soleimani’s death would double “resistance” against the US and Israel, he added.
Iraqis are also mourning the death of Abu Mahdi al-Muhandis, an Iraqi who commanded the Iranian-backed Kataib Hezbollah group and was killed along with Soleimani.
The group issued a warning to Iraqi security forces to “stay clear of American bases by a distance not less [than] 1,000m (0.6 miles) starting Sunday evening”, al-Mayadeen TV reported.