The White House said on Tuesday it was concerned that Iran might be providing Russia with ballistic missiles for use in its war against Ukraine.

Moscow is already receiving Iran’s help with Shahed drones, guided aerial bombs, and artillery ammunition and may be gearing up “to go a step further in its support for Russia”, said National Security Council spokesperson John Kirby.

Moscow has received hundreds of Shahed drones that the Russian military used against Ukraine’s energy facilities and other key infrastructure.

“We are therefore concerned that Iran is considering providing Russia with ballistic missiles now for use in Ukraine,” Mr Kirby told reporters.

Vladimir Putin, in return, is offering Tehran “unprecedented defence cooperation, including on missiles, electronics and air defence", he said.