A huge crowd of mourners poured onto the streets of Tehran on Monday to pay their respects to Qassem Soleim, the country's most powerful military commander who was killed in a US air attack in Iraq last week.
The country's Supreme Leader Ayatollah Ali Khamenei, who has pledged "severe revenge" for the killing, presided over prayers for the slain general, Al Jazeera reported.
Standing next to Iran President Hassan Rouh and Iran's Speaker of Parliament Ali Larij, Khamenei wept at one point beside the flag-draped coffins containing the remains of Soleim and five other "martyrs" killed in Friday's strike in Baghdad.
According to state media, streets of the capital were filled with mourners that many were unable to emerge from underground metro stations.
"There are large crowds at metro stations but as there is also a huge crowd at the street level, it isn't possible to evacuate passengers," metro chief Farnoush Nobakht was quoted as saying.
Addressing the huge crowd in freezing early morning temperatures, Soleim's daughter, Zeinab, warned the US and its ally Israel of facing a "dark day" in the wake of her father's killing last Friday.
"Crazy (Donald) Trump, do not think that everything is over with my father's martyrdom," she said in an address broadcast on state television, referring to the US president.
"The families of US soldiers in the Middle East will spend their days waiting for the death of their children," she added.
The funeral ceremony will continue with Soleim's remains going to the holy city of Qom before his burial on Tuesday in Kerman, his hometown.
The assassination of Soleim triggered a dramatic escalation of tensions in the Middle East and marked the most significant confrontation between the US and Iran in recent years.
( With inputs from ANI )