The assassination of Ismail Haniyeh happened at around 02:00 midnight.
Martyr Haniyeh, who was visiting Iran for the inauguration ceremony of the Iranian president, was stationed in one of the residences for war veterans in the north of Tehran.
He was martyred after a projectile hit his place of residence.
Ismail Haniyeh and one of his bodyguards were martyred after their residence was targeted in Tehran, according to a statement released by the IRGC.
"With condolences to the heroic nation of Palestine and the Islamic nation and the combatants of the Resistance Front and the noble nation of Iran, this morning (Wednesday) the residence of Mr. Dr. Ismail Haniyeh, the head of the political office of the Islamic Resistance of Hamas, was hit in Tehran, and following this incident, he and one of his bodyguards were martyred," the statement reads.
Further investigation into the incident is underway.
Mousa Abu Marzook, a member of the Hamas Political Bureau, has vowed to take revenge for the martyrdom of the chief of the political bureau of the Palestinian Resistance movement Ismail Haniyeh.
The Hamas official stressed that the cowardly assassination of Haniyeh will not go unanswered.
Commenting on the incident, Iranian Foreign Ministry Spokesperson Nasser Kan'ani said that an investigation into the details of this incident by the relevant institutions of the Islamic Republic of Iran is underway.
MP/Alalam channel