Iran has asked Russia to supply its advanced S-400 air defence systems in a personal letter from Supreme Leader Mojtaba Khamenei to President Vladimir Putin, according to a report in The Telegraph.

The letter was delivered in person at the Kremlin on 5 November by Mohsen Rezaei, secretary of Iran's Supreme National Security Council. The Telegraph, citing a senior Iranian official, reported that the S-400 request was the letter's central demand and that Tehran is optimistic Mr Putin will approve a sale.

Neither Moscow nor Tehran has confirmed that air defences were the subject of the letter, and no agreement has been announced. The Kremlin confirmed only that Mr Rezaei handed Mr Putin a message from the Iranian leader, without disclosing its contents.

Iran has sought the S-400, Russia's long-range surface-to-air missile system, for several years. Moscow has so far declined to sell it, reportedly out of concern for its relations with Israel. Iran's foreign minister, Abbas Araghchi, is reported to have raised the same request with Mr Putin during a visit to Moscow in April.

The renewed approach comes as Tehran tries to rebuild air defences exposed as inadequate by American and Israeli strikes during the war that began in February. Iran's ambassador to Moscow, Kazem Jalali, said the Rezaei-Putin meeting lasted three hours and took place in what he called a highly coordinated atmosphere.

The report also said The Telegraph had reviewed confidential documents showing Iranian security agencies had drafted recommendations before the war for strengthening military ties with Russia and China, including bolstering air defence, missiles and drones. For now, the reported negotiations remain unconfirmed by either government, and no delivery timetable exists. Read the report at Clash Report.