"The president, head of the judiciary, and a member of the Guardian Council will assume the duties of Supreme Leader during the vacant period," state-run agency IRNA quoted Mokhber as saying.
Iran's Supreme Leader Ali Khamenei was killed in his office early Saturday morning in a US-Israeli missile attack. Following the supreme leader's death, the Iranian government declared a 40-day national mourning period and a non-working week. The IRGC and the Iranian army vowed to avenge Khamenei's death in published statements.
On Saturday, the US and Israel launched a series of strikes on Iranian targets, including Tehran, causing damage and civilian casualties. Iran launched retaliatory missile strikes on Israeli territory, as well as on US military installations in the Middle East.