Mourners take part in the funeral procession in the Iraqi central city of Karbala on Saturday. AFP

US President Donald Trump on Saturday threatened to hit 52 Iranian sites "very hard" if Iran attacks Americans or US assets after a drone strike that killed Iranian military commander Qassem Soleimani and an Iraqi militia leader, as tens of thousands of people marched in Iraq to mourn their deaths.

US kills Irans most powerful general in Baghdad strike

Thousands of Iraqi's join Baghdad funeral for slain commanders

Showing no signs of seeking to ease tensions raised by the strike he ordered that killed Soleimani and Iranian-backed Iraqi militia leader Abu Mahdi Al Muhandis at Baghdad airport on Friday, Trump issued a threat to Iran on Twitter. The strike has raised the spectre of wider conflict in the Middle East.

Iraqis burns the American flag in the southern city of Basra. AFP

Iran, Trump wrote, "is talking very boldly about targeting certain USA assets" in revenge for Soleimani's death. Trump said the United States has "targeted 52 Iranian sites" and that some were "at a very high level & important to Iran & the Iranian culture, and those targets, and Iran itself, WILL BE HIT VERY FAST AND VERY HARD."

“The USA wants no more threats!” Trump said, adding that the 52 targets represented the 52 Americans who were held hostage in Iran for 444 days after being seized at the US Embassy in Tehran in November 1979 — an enduring sore spot in US-Iranian relations.

Trump did not identify the sites. The Pentagon referred questions about the matter to the White House, which did not immediately respond to a request for comment.

War crime

Meanwhile, Iran's top diplomat said any decision to target the country's cultural sites would be a "war crime", hours after US President Donald Trump threatened such action in a tweet.

"Targeting cultural sites is a WAR CRIME," Mohammad Javad Zarif tweeted in response to a post by Trump warning the US is targeting 52 sites in Iran and will hit them "very fast and very hard" if the Islamic republic attacks American personnel or assets.

Among the mourners in Iraq included many militiamen in uniform for whom Muhandis and Soleimani were heroes. They carried portraits of both men and plastered them on walls and armoured personnel carriers in the procession. Chants of "Death to America" and "No No Israel" rang out.

On Saturday evening, a rocket fell inside Baghdad's heavily fortified Green Zone near the US Embassy, another hit the nearby Jadriya neighbourhood and two more were fired at the Balad air base north of the city, but no one was killed, Iraq's military said. There was no immediate claim of responsibility.

Mourners carry the coffins of Qassem Soleimani and Abu Mahdi Al Muhandis at the Imam Ali shrine in Najaf. AP

Iraq's Kataib Hezbollah militia warned Iraqi security forces to stay away from US bases in Iraq, "by a distance not less than a thousand metres (six-tenths of a mile) starting Sunday evening," reported Lebanese Al Mayadeen TV, which is close to Lebanon's Hezbollah.

Trump said on Friday Soleimani had been plotting "imminent and sinister" attacks on American diplomats and military personnel. Democratic critics said the Republican president's action was reckless and risked more bloodshed in a dangerous region.

Bodies taken to holy cities

A PMF-organised procession carried the bodies of Soleimani and Muhandis, and those of others killed in the US strike, through Baghdad's Green Zone.

US troops from the Army's 82nd Airborne Division wait at Green Ramp before they head out for Middle East. AFP

The top candidate to succeed Muhandis, Hadi Al Amiri, spoke over the dead militia commander's coffin: "The price for your noble blood is American forces leaving Iraq forever and achieving total national sovereignty."

Prime Minister Adel Abdul Mahdi also attended. Mahdi's office later said he received a phone call from Saudi Crown Prince Mohammed Bin Salman and they "discussed the difficult conditions facing Iraq and the region."

Mourners brought the bodies of the two slain men by car to the Shi'ite holy city of Kerbala, south of Baghdad, then to Najaf, another sacred Shi'ite city, where they were met by the son of Iraq's top Shi'ite cleric, Grand Ayatollah Ali Al Sistani, and where Muhandis and the other Iraqis killed will be laid to rest.

Soleimani's body will be transferred to the southwestern Iranian province of Khuzestan that borders Iraq. On Sunday it will be taken to the Shi'ite holy city of Mashhad in Iran's northeast and from there to Tehran and his hometown Kerman in the southeast for burial on Tuesday, state media said.

The US strike followed a sharp increase in US-Iranian hostilities in Iraq since last week when pro-Iranian militias attacked the US embassy in Baghdad after a deadly US air raid on Kataib Hezbollah, founded by Muhandis. Washington accused the group of an attack on an Iraqi military base that killed an American contractor.

Reuters