Khamenei, in power since his father Ali Khamenei was killed at the start of the US-Israeli war against Iran in February, has yet to be seen in public since taking on the top job and his health and influence remain uncertain.But on August 9 and 10 he filled key security posts -- many of which became vacant after previous incumbents were killed in the war -- with loyal, veteran figures hailing from the Revolutionary Guards (IRGC), Iran's ideological army, which has a long history of antagonism with the US.They included Mohsen Rezaei, 71, a former commander of the IRGC for almost all the 1980s war against Saddam Hussein's Iraq and Hossein Taeb, 63, a former Guards intelligence chief who stepped down in mysterious circumstances in 2022.The appointments are "indicative of the adoption of a more risk-ready, confrontational stance", said Jason Brodsky, policy director of the US-based United Against Nuclear Iran (UANI) think tank."These appointments are demonstrative of Iran believing it will be in a wartime footing for the foreseeable future," he said, adding that Khamenei has brought back "the old guard" of the IRGC.It remains to be seen where the appointments will leave diplomacy with the US, after the expiry of a 60-day deadline for an agreement. The talks have so far been led by parliament speaker Mohammad Bagher Ghalibaf who has become seen as a less hardline figure.Here AFP looks at the key figures in Iran's security apparatus:- Supreme national security council secretary Mohsen RezaeiCommander of the Revolutionary Guards in the 1980s and 1990s, Rezaei has never been far from prominence, with his stern face and black beard a familiar presence for Iranians on TV.His forays into mainstream politics have not been successful, with several failed presidential bids, and his sudden elevation to the key post once held by Ali Larijani, who was killed in the war, surprised some observers.In April, he warned that Iran would sink American ships in the Strait of Hormuz if the United States decided to "police" the key shipping bottleneck and in June said every American attack would be met by a "deluge" of missiles.A 2020 US sanctions designation said he is suspected of involvement in the 1994 attack against a Jewish community centre in Argentina.- Basij commander Hossein TaebTaeb, a cleric, was named commander of the Basij, the IRGC's vast youth militia, which has become notorious as an enforcer of security in Iranian neighbourhoods.He had led the intelligence arm of the IRGC for almost one-and-a-half decades up until June 2022 when he was suddenly replaced.