CNN  — 

At least 56 people were crushed to death Tuesday when a stampede broke out at the funeral of the Iranian commander killed in a US drone strike.

State-run Iranian broadcaster IRINN reported 35 men and 21 women died, and another 213 people were injured, at the funeral procession for Qasem Soleimani in his hometown of Kerman. Images showed tens of thousands of people pouring into the streets to honor the slain commander, a revered figure in Iran.

The chaos forced Iranian authorities to delay Soleimani’s burial, four days after a US drone strike at Baghdad’s airport killed him in a dramatic escalation of tensions between Tehran and Washington, and US allies in the Middle East. The strike also killed Abu Mahdi al-Muhandis, the deputy head of the Iranian-backed Iraqi Popular Mobilization Forces (PMF).

The coffins of Qasem Soleimani and others killed in a US drone strike are carried by mourners in Kerman, Iran, on Tuesday.

As head of the Islamic Revolutionary Guards Corps (IRGC) Quds Force, Soleimani became the architect of Tehran’s proxy conflicts in the Middle East.

Iran has vowed revenge for the killing, which it describes as an “act of war” and “state terrorism.”

US forces and air defense missile batteries across the Middle East were on high alert overnight Monday to possibly shoot down Iranian drones as intelligence mounted about a threat of an imminent attack against US targets, two US officials told CNN.

US officials say the strike against the general was carried out to prevent an “imminent” attack in the region that would have put American lives at risk, but they have declined to provide details about the intelligence.

Iranian mourners hold placards at the funeral of Qasem Soleimani in Kerman, Iran, on Tuesday.

US intelligence also has observed Iran moving military equipment, including drones and ballistic missiles, over the past several days. US officials said the movement may be an Iranian effort to secure its weapons from a potential US strike, or put them in positions to launch their own attacks.

The Pentagon blamed Soleimani and his Quds Force for attacks on coalition bases in Iraq in recent months, including the December 27 strike that culminated in the deaths of an American contractor and Iraqi personnel. He was also blamed for the December 31 attack on the US Embassy in Baghdad, and in addition to the hundreds killed in his time as a commander, thousands more were wounded, the Pentagon said.