Iran and Russia are in talks over a deal to send advanced air defence systems to Tehran, The Telegraph can reveal.

The Islamic Republic was “optimistic” that Vladimir Putin would finally deliver the long-awaited S-400 air defence systems it had sought for years, a senior Iranian official said.

Mojtaba Khamenei, Iran’s supreme leader, dispatched Mohsen Rezaei, his security chief, to the Kremlin on Thursday with a personal letter whose central demand, according to the official, was the supply of the weapon.

The negotiations over a deal contradict claims by Donald Trump that Russia is not helping Iran “at all”.

Mr Rezaei said after the Moscow talks: “Important regional issues were discussed with Mr Putin, and significant conversations took place regarding the post-war period and regional security arrangements.”Discussions were also held about the construction of a new gas pipeline between Russia and Iran.

Vladimir Putin with Mohsen Rezaei, the Iranian security chief, who visited the Kremlin on Thursday Iran is known to have cut a number of recent deals with Russia for the supply of weapons. They appear to be part of long-term plans to survive a war with the US and preserve the Islamic Republic.

The Telegraph can reveal that Iranian officials were presented with proposals for surviving war with the US, including strengthening military ties with Russia.

Confidential documents show how security officials drew up recommendations to build “strategic relations, especially military ones, with independent global powers such as China and Russia” able to blunt American pressure.

The recommendations were produced by a secret committee of the Iranian parliament before the US and Israel started the war on Iran in February, and focused on bolstering “air defence, missiles and drones”.

The fresh request for S-400s is crucial to Iran’s defence policy. US and Israeli strikes have destroyed its air defences and revealed its inability to protect its skies, nuclear sites and commanders including Ali Khamenei, the assassinated former supreme leader.

The S-400 could help Iran restore its diminished air defences, which have been hit repeatedly by the US and Israel Moscow has dangled such sales for years while stopping short of delivery, wary of rupturing ties with Israel and the region, analysts and regional officials said.

Analysts say Russia may be reluctant to part with the systems for its own reasons. Its air defences are under sustained strain from Ukrainian long-range drone and missile attacks on refineries, airbases and other sites, leaving Moscow little to spare, regardless of Tehran’s desire for its most capable batteries.

On Thursday, leaked Russian defence industry documents revealed how Russia had been building helicopter-launched missiles for Iran.

Russian state-owned factories are making specialised missile launch equipment for the Islamic Republic under an export contract its paperwork lists under the code “K-10” – the designation, one of the documents says, for Iran.

The hardware includes launch units for the LMUR, or Product 305, a precision-guided missile. A 2024 delivery schedule allocates power units for 90 twin-rail launchers to a Russian plant with Iran as the end customer, for shipment by December 2025.

Mr Trump has downplayed the Russia-Iran relationship as he has sought to justify direct talks between the US and Moscow to help end the war in Ukraine.

On Oct 12, the US president dismissed warnings of Russian and Chinese help as “at a very low level, but I don’t believe they are at all”, and on Oct 21 Putin assured Steve Witkoff, the US envoy, that “if we can do anything for settling this crisis, we will be glad to help”.

The Iranian war planning memo reviewed by The Telegraph sets out how Iran can use alliances to survive a major conflict.

It says: “The Iranian people’s resistance to foreign pressure over the past four decades has shown that a strategy of ‘collapse from within’ cannot easily succeed.”The memo continues that “new global powers such as China and Russia, which refuse to follow the US agenda, have given Iran more room to manoeuvre internationally”.

Putin, pictured on Wednesday with Patriarch Kirill, the Orthodox church head, could finally deliver S-400 air defence systems to Iran Responding “intelligently” to US strategy, the document argues, “requires the following measures”: strengthening the “resistance economy” and reducing dependence on oil revenues, building “strategic relations, especially military ones, with independent global powers such as China and Russia”, bolstering “air defence, missiles and drones”.

It also says Iran must use “public and media diplomacy to expose the contradictions in the behaviour of the United States and the Zionist regime”, and changing “the West’s current belief that the country is in a weak position”.

Regionally, it says, Iran “should also expand its relations with its neighbours to stop a united anti-Iran front from forming” and “play a bigger role” in bodies such as the Shanghai Cooperation Organisation.

The Middle East, the memo says, holds “about 60 per cent of the world’s oil reserves and 40 per cent of its gas reserves”, along with “three of the world’s strategic chokepoints: the Strait of Hormuz, the Bab el-Mandeb Strait and the Suez Canal” through which “roughly one-third of maritime oil trade and container shipping” passes.

“Washington currently sees at least two of them as under threat,” it says, adding that “West Asia has by no means lost its importance for the West”.

Any change in the regional balance of power, it warns, “directly affects energy security, the global economy and competition among the great powers” – the logic behind Iran’s closure of Hormuz in late February.

“Washington knows that, in the end, the option for dealing with Iran’s nuclear issue is diplomacy,” it says, describing a US mix of “defence diplomacy with its regional partners and allies”.

The aim, it argues, is to pave the way for Israel’s “integration into the region, normalisation of relations, and more cooperation in areas such as infrastructure, ports, roads, water, agriculture and technology”.

On sanctions, the memo strikes a defiant note, calling their effects “both damaging and constructive”.

They “slowed the development of the country’s defence technologies” and made buying “fighter jets and needed parts” nearly impossible, it reads, “yet this also created opportunities”, pushing Iran toward home-built systems “such as the Bavar-373” air defence platform and drones “like the Shahed-136 and Ababil”. The sanctions, it says, “never stopped it, and they even pushed the country towards self-sufficiency”.