Iran is to restart activities at its controversial Arak heavy-water reactor, the head of the country’s nuclear agency announced on Sunday.

Heavy water can be used to make plutonium, an important ingredient in the construction of nuclear weapons.

Under the terms of the landmark 2015 nuclear accord, Tehran agreed to repurpose the facility towards research and medicine.

But in the latest escalation over the Islamic Republic’s nuclear ambitions, Ali Akbar Salehi, the head of the Iranian Atomic Energy Organisation, told lawmakers on Sunday that it would renege on the commitment, according to the semi-official ISNA news agency.