Benjamin Netanyahu, the Israeli prime minister, said yesterday that Iran was only six or seven months away from having most of the fuel it needed to build a nuclear weapon, as he took his appeal for the US to take a tougher line against Iran directly to the American public.

Appearing on two talk shows, Mr Netanyahu stepped up his demand that President Barack Obama set a “red line” for when he would take military action against Iran’s nuclear programme. “You have to place that red line before them now, before it’s too late,” he said on NBC.

He was speaking as the commander of Iran’s Revolutionary Guards warned Isreal that “nothing would remain” of the country if it were to attack Iran. Brigadier General Mohammad-Ali Jafari also said Iran would strike US bases in the region in the event of an Israeli attack.