• Mourners shout 'No No Israel' and 'No No America'
• US urges citizens to leave Iraq on security grounds
• Senior Iranian officer threatens to punish any Americans 'within reach'
• Cites 35 possible targets including Gulf oil region

BAGHDAD: Tens of thousands of people marched in Baghdad on Saturday to mourn Iran's military chief Qassem Soleimani and Iraqi militia leader Abu Mahdi al-Muhandis, killed in a US air strike that has raised the spectre of wider conflict in the Middle East.

By ordering Friday's air strike on the commander of the Iranian Revolutionary Guard's foreign legions, President Donald Trump has taken Washington and its allies, mainly Saudi Arabia and Israel, into uncharted territory in its confrontation with Iran and its proxy militias across the region.

Gholamali Abuhamzeh, a senior commander of Iran's elite Revolutionary Guards, said Tehran would punish Americans "wherever they are in reach", and raised the prospect of possible attacks on ships in the Gulf.

The US Embassy in Baghdad urged American citizens to leave Iraq following the strike at Baghdad airport that killed Soleimani. Dozens of American employees of foreign oil companies left the southern Iraqi city of Basra on Friday.

Close US ally Britain warned its nationals on Saturday to avoid all travel to Iraq, outside the autonomous Kurdistan region, and to avoid all but essential travel to Iran.

The United States and its allies have suspended training of Iraqi forces due to the increased threat, the German military said in a letter seen by Reuters late on Friday.

Soleimani, a 62-year-old general, was Tehran's pre-eminent military commander and - as head of the Quds Force, the foreign arm of the Revolutionary Guards - the architect of Iran's spreading influence in the Middle East.

Muhandis was the deputy commander of Iraq's Popular Mobilisation Forces (PMF) umbrella body of paramilitary groups.

An elaborate, PMF-organised procession carrying the bodies of Soleimani, Muhandis and other Iraqis killed in the US strike took place in Baghdad's heavily fortified Green Zone.

Mourners included many militiamen in uniform for whom Muhandis and Soleimani were heroes. They waved Iraqi and militia flags. They also carried portraits of both men and plastered them on walls and armoured personnel carriers in the procession, and chanted, "No No Israel" and "No No America".

Prime Minister Adel Abdul Mahdi and Iraqi militia commander Hadi al-Amiri, a close Iran ally and the top candidate to succeed Muhandis, attended.

Mourners later brought the bodies by car to the Shi'ite holy city of Kerbala south of Baghdad. The procession was to end in Najaf, another sacred Shi'ite city where Muhandis and the other Iraqis will be laid to rest.

Soleimani's body will be transferred on Saturday 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.

Trump said on Friday Soleimani had been plotting what he called imminent and sinister attacks on American diplomats and military personnel. Democratic critics of the Republican president said Trump's order was reckless and that he had raised the risk of more violence in a dangerous region.

The US strike followed a sharp increase in US-Iranian hostilities in Iraq since last week when pro-Iranian militia attacked the US Embassy in Baghdad following a deadly US air raid on the Kataib Hezbollah militia, founded by Muhandis.

'VITAL AMERICAN TARGETS'

On Friday, Iranian Supreme Leader Ayatollah Ali Khamenei vowed harsh vengeance against the "criminals" who killed Soleimani and said his death would intensify the Islamic Republic's resistance to the United States and Israel.

Abuhamzeh, the Revolutionary Guards commander in Kerman province, mentioned a series of possible targets for reprisals including the Gulf waterway through which a significant proportion of shipborne oil is exported to global markets.

“The Strait of Hormuz is a vital point for the West and a large number of American destroyers and warships cross there," Abuhamzeh was quoted as saying on Friday evening by the semi-official news agency Tasnim.

"Vital American targets in the region have long since been identified by Iran...Some 35 US targets in the region as well as Tel Aviv are within our reach," he said, referring to Israel's largest city.

A senior figure in Lebanon's heavily armed Hezbollah movement said retaliation by the Iran-backed "axis of resistance" to Soleimani's killing would be decisive, al-Mayadeen TV reported on Saturday.

Mohamed Raad, leader of Hezbollah's parliamentary bloc in Lebanon, was referring to a swathe of Iranian-aligned militias from Lebanon to Yemen that have bolstered Tehran’s military clout across the Middle East.

'REVENGE ON THE MURDERERS'

Many Iraqis condemned the US 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 while claiming to fight terrorism," said one of the marchers, Ali al-Khatib.

"It is necessary to take revenge on the murderers. The martyrs got the prize they wanted - the prize of martyrdom."

Many Iraqis also voiced fear of being engulfed in a major US-Iranian conflict, and of militia reprisals against 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.