Israel’s defense minister said Tuesday that the country had interpreted Iran’s conversion of some enriched uranium to fuel rods for civilian use as evidence that Iran had delayed ambitions to build a nuclear weapon.

The assertion, by Defense Minister Ehud Barak in an interview with The Daily Telegraph, a British newspaper, amounted to the first explanation from him as to why he and Prime Minister Benjamin Netanyahu softened their position in September over the possibility of a military strike to thwart what they called Iran’s drive toward imminent nuclear weapons capability.

Their tough position on Iran, which they consider Israel’s most dangerous enemy, had generated tensions with the Obama administration, which has contended that Iran is many months away from the ability to make a nuclear weapon.

Mr. Barak, who was visiting London, was quoted by the newspaper as saying an immediate crisis had been averted this summer because Iran had chosen to use a third of its enriched uranium for use as fuel rods in a medical research reactor. The conversion of that uranium, which was reported by the International Atomic Energy Agency in August, makes it much more difficult to use militarily.