The United States’ strikes on three key Iranian nuclear sites on Sunday failed to destroy underground facilities, and set Tehran’s nuclear programme back only by a few months, according to an assessment of a confidential American intelligence report.

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 seven people briefed on it.

The US military had deployed its B-2 stealth bombers to drop bunker-buster bombs on the three nuclear facilities in Iran - Natanz, Fordow, and Isfahan.