The United States and allies warned Iran on Friday that major Western economies will pile new sanctions on Tehran if it moves forward with an advancing plan to provide ballistic missiles to Russia for its war with Ukraine.

The Biden administration has raised alarms for months that Russia is seeking close-range ballistic missiles from Iran as Moscow struggles to replenish its dwindling supplies.

The US has yet to confirm that missiles have moved from Iran to Russia but US officials are alarmed by comments by Iranian officials that suggest that a deal is imminent.

One action that the G7 (Group of Seven) countries are mulling is to prohibit Iran Air, the country’s national air carrier, from flying to Europe, according to a senior Biden administration official.

The official, who was not authorised to comment and insisted on anonymity, declined to preview other sanctions that the US are considering beyond describing the potential action as “significant measures”.

The US and Europe already impose extensive sanctions against Iran targeting individuals as well as limiting the country’s access to trade, financial services, energy, technology and other sectors.

The sanctions on Iran are arguably the most extensive and comprehensive set of sanctions that the US maintains on any country, with thousands of individuals and entities targeted.