The US military strikes on three of Iran’s nuclear facilities last weekend did not destroy the core components of the country’s nuclear program and likely only set it back by months, according to an early US intelligence assessment that was described by three people briefed on it.

In the wake of recent strikes by Israel and the United States on Iranian cities, military sites and nuclear facilities, a troubling paradox has emerged: actions intended to prevent Iran from acquiring nuclear weapons may actually be accelerating its pursuit of them and encouraging other countries to follow suit.