US sent private warning to Iran over nuclear programme

According to Axios, the Iranian response “addressed some of the concerns and somewhat eased anxieties over the Iranian research and development”.

A US official told Axios: "We do not see indications that Iran is currently undertaking the key activities that would be necessary to produce a testable nuclear device.

"We take any nuclear escalation by Iran incredibly seriously. And, as the President has made clear, we are committed to never letting Iran obtain a nuclear weapon—and we are prepared to use all elements of national power to ensure that outcome," the official added.

Last month, leaked documents revealed that one of Iran’s main nuclear facilities is undergoing a massive expansion that could triple or quadruple the country’s production of enriched uranium, providing Tehran with new options for quickly developing a mass arsenal of nuclear weapons.

The major project inside Iran’s most fortified nuclear site, the Fordow enrichment plant, would significantly accelerate Iran’s nuclear mission, according to confidential documents and analysis obtained by the Washington Post.

In March this year, US and Israeli intelligence said they believed Iranian scientists were engaging in advanced research including computer modeling and metallurgical research that could be used for nuclear weapon development.