Mohamed Ismail Darwish will replace eliminated Hamas leader Ismail Haniyeh, the terror group announced Tuesday, according to Al Arabiya.
Darwish, who is also known as Abu Omer Hassan, currently serves as the head of Hamas' Shura Council, after the Council's former head, Osama al-Mazini, was eliminated in December.
Al-Mazini was a senior member of the terrorist organization who previously handled the Gilad Shalit case when he was held by Hamas, and served as a minister in the government that operated in Gaza.
Darwish's appointment is temporary, and in effect until the Hamas leadership can hold elections next year.
Last week, the New York Times reported that over 24 people were arrested by the Revolutionary Guards, including senior intelligence and military officers, on suspicion of being involved in the assassination of Hamas leader Ismail Haniyeh.
Among the detainees are senior officers, some from the intelligence wing of the Revolutionary Guards. In addition, members of the staff of the guest house where Haniyeh was staying were arrested.
According to a report in the British Telegraph, the Mossad recruited agents from the Revolutionary Guards for this mission, and they planted explosive material about two months ago - after the helicopter crash which killed the previous President of Iran, Ebrahim Raisi.
According to Iranian sources, the plan was to assassinate Haniyeh upon his arrival at Raisi's funeral but the plan was postponed.
Subsequently, the Mossad sent two agents to plant explosives in three different rooms in the guesthouse in northern Tehran.
The agents were sent to these rooms due to the high probability that Haniyeh would stay in them. According to the report, Iranian officials hold footage of the agents moving between several rooms within minutes. After planting the explosives, the agents, suspected of working in the VIP Protection Unit of the Revolutionary Guards, fled Iran - but maintained a source inside the country.