“Despite repeated requests from the Iranian side for various types of weapons – air defence systems and fighter jets – none of this has been transferred to Iran by Russia to date,” Smagin said.

Partly due to its entanglement in Ukraine and its growing ties with other regional players, including Saudi Arabia, Moscow has shown little urgency on propping up Iran, even as Tehran’s position has weakened after blows against its key proxy, the Lebanese movement Hezbollah.

I think that Russia is probably kind of short on functioning air defense systems herself.