Iran will have a range of advanced military equipment it can choose from if the UN arms embargo ends in October.
High on Tehran's list will be highly manoeuvrable Russian-made fighter aircraft, as well as some of its most advanced surface-to-air missiles.
But Chinese weapons systems are likely to provide tough competition to Russia's offering.
Chinese fighter jets and missiles may not be as advanced as those produced in Russia, but their lower cost could prove tempting to cash-strapped Tehran.
Below are some of the jets, missiles and submarines singled out by experts at the International Institute for Strategic Studies as potential purchases.
- Highly manoeuvrable multi-role variant of the Flanker aircraft family
- Similar to American F-15E Strike Eagle
- Deep interdiction and strike missions
- Air-to-air fighter
- All weather. Good reliability
- Operational with Russian Air Force in Syria
China's J-10 Firebird
- Light, fast and agile
- In service with Chinese air force and navy
- Was a specialised fighter but now capable of ground attack, too
- Radar is said to be very good – Chinese claim better than European Typhoon
- Single seat, single engine
- Top speed of about 2,700kph
- Allegedly copied from an early Israeli design
- All-out fighter jet with advanced avionics and weapon systems
- Has unique precision targeting system
- Able to conduct independent missions
- Cheaper but less capable than the Su-30SM
China and Pakistan's JF-17 Thunderbird
- Cheapest option to buy
- Uses include interception, anti-ship, ground attack and reconnaissance
- Combat proven – Pakistani JF-17s allegedly shot down Indian MiG-21 and Su-30M in 2019
- Available for export
Air defence missiles
- One of the world's most advanced anti-aircraft missiles
- Russia engaged in major export drive and will sell to Iran if official request made
- Radar system can track 100 targets simultaneously
- Effective at extremely long ranges of more than 300km
- Maximum velocity 7,240kph carrying large 180kg warhead
- One central system can control 72 launchers and 384 missiles
Russia's S-300PMU2 Grumble
- Old but remains a potent anti-aircraft missile
- Significantly cheaper than S-400
- Russia capable of producing second-hand S-300 systems for export as per Syria
- Can defend against cruise missiles and aircraft and can intercept ballistic missiles.
- Criticised by Syrian official as ineffective against Israeli air attacks
China's FD-2000 Fang Dun
- Well-regarded medium to long-range missile
- Seen as somewhere between S-400 and S-300 in capability
- Maximum range 200km with large 180kg warhead
- Maximum speed 5,150kph
- May not yet be ready for export
Russia's Varshavyanka Kilo class upgrade
- Anti-shipping, anti-submarine vessel excellent in shallow waters such as the Gulf
- Project 636 Varshavyanka-class is modernised variant of older Kilo class operated by Iran
- Extended combat range, can strike land targets
- Speed of 20 knot and can dive 300 metres. Crew of 52
- Carries cruise missiles, torpedoes and mines
- Iran may choose to simply upgrade its existing hulls rather than buy a new model
China's Yuan class
- Among the quietest diesel-electric submarines in service
- Able to hide underwater for several days
- Excellent in shallow waters close to coastlines
- Capable of firing cruise missiles against ships
- Anti-submarine role
Iran is particularly interested in faster, longer-range anti-ship and land-attack missiles.
If the embargo is not renewed, Iran will likely want to invest in new weapons to supplement its own, domestically-produced missiles.
Both Russia and China has been developing advanced missiles capable of hitting targets at sea or on land, over extreme distances.
Iran has already shown willingness to use long-range missiles, and new weapons would add to Tehran's defensive and offensive capabilities in the region.
Chinese or Russian missiles would give Iran the ability to hit targets hundreds of kilometres away.
Iran could seek to play the two powers against one another in order boost its forces as cheaply as possible.
Russia’s Yakhont missile
- Supersonic anti-ship cruise missile
- Fire and forget with full autonomy
- Supersonic speed, sea skimming
- Used on warships, submarines and land launchers
China's YJ-18 Eagle Strike missile
- Similar to Russian Klub cruise missile
- Anti-ship and land attack
- Possible range of 480km with 'sprint' range of 40km
- Launch from submarine torpedo tube
- Carries a 300kg high-explosive warhead
- Anti-radar warhead can destroy electronics at short range
- Availability for export uncertain