Israel escalated its rhetoric over Iran’s nuclear programme at the weekend, with a senior official warning that it was prepared to launch a unilateral military strike against Iran.

Although Israel has talked many times in the past about its willingness to take military action on its own, the new warning comes ahead of crucial diplomatic talks with Iran on Wednesday which US officials say are “close” to success.

At the same time, Benjamin Netanyahu, Israeli prime minister, took to the US airwaves again yesterday to blast the Obama administration over the prospect of a deal with Iran and to lobby public opinion against any agreement. Fran?ois Hollande, the French president, also said that his country intended to maintain its tough stance in this week’s negotiations as he began a three-day visit to Israel. France was blamed for the collapse of the first round of talks this month.