"The flames of the American-Israeli bombs that were dropped on the heads of the oppressed wounded Palestinians at Gaza's al-Ahli Baptist Hospital would soon devour Zionists," Raeisi wrote in a post on X, formerly known as Twitter, on Tuesday.
Earlier in the day, at least 500 civilians, mainly women and children, were killed by Israeli airstrikes on the facility amid a relentless war by the regime on the besieged Gaza Strip, the territory's health ministry said.
The actual death toll could be far higher since, according to the ministry, "hundreds of victims are still under the rubble."
The strikes came while thousands of civilians were seeking medical treatment and shelter at the hospital from incessant Israeli airstrikes.
The war had already killed thousands of people, including hundreds of women and children.
"The silence of no noble person is permissible in the face of this war crime," Raeisi added, saying the Islamic Republic had declared Wednesday a day of public mourning over the tragedy.
Foreign Minister Hossein Amir-Abdollahian, meanwhile, wrote in a post on X that, in the aftermath of the "appalling crime," time had come for "the humanity to unite internationally against this bogus regime...and its killing machine," calling the Israeli regime "more hateful than [the Takfiri terrorist group of] Daesh."
Also on Tuesday, the Foreign Ministry condemned the deadly atrocity in the strongest terms, calling the massacre as a "savage war crime" and an instance of "genocide."
MP/PressTV