In a letter to the students, Khamenei described them as part of the "Resistance Front" destined to win "with the permission of God," expressing solidarity and empathy for their support of Palestinians.
The ICJ amended an earlier order and demanded Israel immediately halt its military offensive in Rafah, a city in southern Gaza where Tel Aviv sent forces May 6.
Three like-minded European countries - Spain, Ireland and Norway - have announced they will formally recognise the Palestinian state, seven months after the outbreak of the war in Gaza.
After the news of his death, state television showed photos of Raisi with the voice of a man reciting the Quran in the background and footage of faithful praying in Raisi's home city.