US Secretary of State Marco Rubio says that Iran was pursuing a nuclear weapon behind a “conventional shield”, which Washington has “substantially eroded”.

“Iran’s desire to build a nuclear weapon was going to be effectuated behind a conventional shield,” Rubio says, testifying before the US Senate Foreign Relations Committee.

“They were going to build for themselves so many missiles, so many drones, so many conventional weapons … that at that point, there’s nothing you could do about it,” he adds, adding that Iran’s plan was to rely on conventional arms to deter action against its nuclear weapons programme.

Rubio says that the US military campaign “substantially degraded” Iran’s capability to build missiles and drones.

“They still have a lot of drones,” he adds, noting that they are “easy to make”.