The stampede erupted at a funeral procession for the top Iranian general killed in a US airstrike last week, Iranian state tv reported.
Iranian state TV says at least 56 people have been killed and more than 200 injured in a stampede at the funeral procession for General Qassem Soleimani, who was killed in a US drone strike.
The TV network says the stampede erupted in Kerman, the hometown of Soleimani where the procession was underway on Tuesday. Iranian media originally said 35 people had been killed.
His funeral was later postponed but no new timing was given.
The remains of Iran's most powerful general arrived Tuesday in Kerman for his burial following an unprecedented outpouring of grief in a three-day state funeral procession.
Thousands gathered in Iranian city Kerman, the hometown of the slain General Qassem Soleimani, where his final resting place was being prepared.
Soleimani's remains and those of the others killed in last week's US airstrike were brought to a central square in Kerman, a desert city surrounded by mountains where he will be buried later on Tuesday.
Khameini prays over casket
At yesterday's funeral procession, Iran's Supreme Leader Ayatollah Ali Khamenei prayed over the caskets of the top Iranian general Qassem Soleimani and others killed in a U.S. airstrike near the Baghdad airport last week.
The general's successor, Easmail Ghaani stood near his side, as did Iranian President Hassan Rouhani and other top leaders in the Islamic Republic.
Khamenei wept at one point during the traditional Muslim prayers for the dead. The crowd and others wailed. Afterwards, the crowd screamed: "Death to America!''
The funeral drew crowds of millions in the Iranian capital on the second day of funeral processions, according to police estimates. Aerial footage and journalists present also suggested a turnout of roughly a million people.
Authorities later brought the remains to the holy city of Qom where another crowd came out for the general.
Soleimani's daughter threatens the US
Earlier in the day, Soleimani's daughter threatened an attack on the U.S. military in the Mideast while speaking to a crowd of hundreds of thousands in Tehran that stretched as far as the eye could see.
“The families of U.S. soldiers in the Middle East will spend their days waiting for the death of their children," Zeinab Soleimani said.
The day before, mourners, spreading across several kilometres, chanted slogans anti-American and anti-Israeli slogans against a background of funeral songs broadcast over loudspeakers.
This was the first time Iran honoured a single man with a multi-city ceremony since the 1989 funeral for the Islamic Republic founder Ayatollah Ruhollah Khomeini. According to Iranian state tv, millions of people took to the streets on Sunday morning as his body was passed through the frantic crowds.