By Ahmed Aboulenein and Maha El Dahan
BAGHDAD (Reuters) - Thousands of people marched in Baghdad on Saturday to mourn Iran's slain military commander Qassem Soleimani, Iraqi militia leader Abu Mahdi al-Muhandis and others killed in a U.S. air strike.
Friday's attack on Baghdad airport, authorised by U.S. President Donald Trump, signalled a major escalation in a Middle East "shadow war" between Iran and the United States and American allies, mainly Israel and Saudi Arabia.
The U.S. Embassy in Baghdad urged American citizens to depart Iraq following Soleimani's killing and dozens of American employees of foreign oil companies left the southern Iraqi city of Basra on Friday.
On Saturday, close U.S. ally Britain warned its nationals to avoid all travel to Iraq, outside the autonomous Kurdistan region, and avoid all but essential travel to Iran.
Soleimani, a 62-year-old general, was Tehran's most prominent military commander and the architect of its spreading influence in the Middle East. Muhandis was the deputy commander of Iraq's Popular Mobilisation Forces (PMF) umbrella body of paramilitary groups.
U.S.-Iranian hostilities have intensified in Iraq since last week when pro-Iranian militia attacked the U.S. Embassy in Baghdad following a deadly U.S. air raid on the Kataib Hezbollah militia, founded by Muhandis.
A senior Trump administration official said Soleimani had been planning imminent attacks on U.S. personnel across the Middle East. U.S. Democratic party critics said the order by the Republican president was reckless and that he had raised the risk of more violence in a dangerous region.
An elaborate, PMF-organised procession to mourn Soleimani, Muhandis and the others began in Baghdad's heavily fortified Green Zone on Saturday. It will proceed by car to the Shi'ite holy city of Kerbala and end in Najaf, another sacred Shi'ite city where Muhandis and the other Iraqis killed will be buried.
SOLEIMANI BURIAL IN HOMETOWN KERMAN
Soleimani's body will be transferred to the southwestern Iranian province of Khuzestan that borders Iraq, then on Sunday to the Shi'ite holy city of Mashhad in the northeast and from there to the capital Tehran and on to his hometown Kerman in the southeast for burial on Tuesday, Iranian state media reported.
In Baghdad, marchers waved Iraqi and militia flags in a sombre atmosphere, with Prime Minister Adel Abdul Mahdi and Iraqi militia commander Hadi al-Amiri, a close Iran ally and the top candidate to succeed Muhandis, attending the procession.
Friday's air strike divided Iraqi opinion.
Many condemned the U.S. attack, regarding Soleimani as a hero for his role in defeating the Islamic State militant group that had seized wide swathes of north and central Iraq in 2014.
"The broad participation in this procession proves the public's condemnation of America and its allies for their human rights abuses whilst claiming to fight terrorism," said Ali al-Khatib, a mourner in the Iraqi capital.
"It is necessary to take revenge on the murderers. The martyrs got the prize they wanted - the prize of martyrdom."
Other Iraqis at first reacted with joy to the U.S. strike only to become quickly fearful of the fall-out, particularly for those involved in months of street protests against the Iranian-backed Baghdad government over alleged misrule and corruption.
They said that Soleimani and Muhandis had backed the use of force against unarmed anti-government protesters last year and established militias that demonstrators blame for many of Iraq's social and economic woes.
Protesters now worry they could become an easy target for reprisals from Shi'ite militias who had been portraying the wave of anti-government demonstrations as a U.S. conspiracy.
They are also angry at Washington for killing the men on Iraqi soil, possibly plunging Iraq into another war.
"These acts are the beginning of American-Iranian conflict in Iraq, after dominating Iraq and belittling Iraq's role," said one protester in Baghdad's central Tahrir Square (NYSE:SQ).
"This air strike will have grave consequences."