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Dozens of people died in a stampede Tuesday during the funeral procession for Qassem Soleimani, the top Iranian commander killed in an American airstrike last week, emergency service officials told state media.

Soleimani's burial was postponed after as many as 50 people were killed and more than 200 others were injured during the crush in his hometown, Kerman, Iran's ISNA news agency said, quoting the chief coroner for Kerman province, Abbas Amian, according to Reuters.

Even before the deaths, Soleimani's funeral procession was a deeply emotional, hourslong event. It was the latest mass outpouring of anger and grief across the country after the U.S. drone strike that killed Soleimani and others near Baghdad airport in neighboring Iraq.

On Monday hundreds of thousands of mourners turned out for a similar procession in the capital, Tehran.

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Iranian officials have vowed to avenge Soleimani, who was head of the Quds Force, an elite unit of its Revolutionary Guard.

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He was a hugely influential figure across the Middle East and seen by some Iranians as a hero who had restored national pride. He spent decades overseeing the development of Iran-backed proxies in Lebanon, Syria and the Gaza Strip that now face Israel to the north and the south.

The United Kingdom's ambassador to Iran, Rob Macaire, tweeted he was "deeply sorry to hear about the loss of life" during the funeral in Kerman.

Deeply sorry to hear about the loss of life at today’s events in Kerman. All condolences to those affected.

از شنیدن خبر از دست دادن جان عده ای در مراسم کرمان عمیقاً متاسفم و ابراز همدردی می نمایم — Rob Macaire (@HMATehran) January 7, 2020

Iranian leaders have promised revenge against the United States for Soleimani's death. The country has also announced that it will abandon limitations on enriching uranium that were negotiated under a landmark nuclear deal in 2015.

Trump has threatened to attack cultural sites in Iran if it carries out its threats of retaliation, something the country's foreign minister, Mohammad Javad Zarif, said would constitute a "war crime."

Protocol I of the Geneva Conventions prohibits the targeting of "historic monuments, works of art or places of worship which constitute the cultural or spiritual heritage of peoples," while also prohibiting making such sites the "object of reprisals."

On Sunday, lawmakers in Iraqvoted to end the U.S. military presence in the country.

There are around 5,000 American personnel in Iraq to combat the Islamic State militant group, a fight Soleimani is credited with aiding. A further 3,000 service members were sent to the region Friday in the wake of Soleimani's death and the broader unrest.

This is a developing story — check back for updates soon.