The leader of Iran's paramilitary Revolutionary Guard was killed, Iranian state television reported, in a major body blow to Tehran's governing theocracy and an immediate escalation of the nations' long-simmering conflict

An anchor read a statement saying: "The news of assassination and martyrdom of Gen Hossein Salami was confirmed," but did not elaborate. Another top Guard official, as well as two nuclear scientists, were also feared dead

Israeli leaders said the attack was necessary to head off what they described as an imminent threat that Iran would build nuclear bombs, and they warned of a reprisal that could target civilians in Israel

In Washington, the Trump administration, which earlier cautioned Israel against an attack amid continuing negotiations, said that it had not been involved in the attack and warned Iran against retaliations against US interests or personnel

Multiple sites in the capital were hit in the attack, which Israeli Prime Minister Benjamin Netanyahu said targeted both nuclear and military sites. Also targeted were officials leading Iran's nuclear programme and its ballistic missile arsenal

Sounds of explosions were heard again within hours. It wasn't immediately clear if it was air defence systems going off or another attack

The assault came amid warnings from Israel that it would not permit Tehran to build a nuclear weapon, though it remains unclear how close the country actually is to achieving that

Netanyahu said in an address on YouTube that the attacks will continue "for as many days at it takes to remove this threat"

The attack followed increasing tensions that led the US to pull some diplomats from Iraq's capital and to offer voluntary evacuations for the families of US troops in the wider Middle East