ISLAMABAD: The Iranian embassy in Pakistan has said attacks by the US and Israel in June killed over 1,100 people and were aimed at toppling the regime in Tehran.

The comments were made by the Iranian defence attaché in Islamabad, who briefed military personnel of various foreign missions over the 12-day war on Thursday.

On the same day, NBC News reported that a new US assessment has found that US strikes mostly destroyed one of three targeted Iranian nuclear sites, but the other two were not as badly damaged.

Col Moshen Shahabi, the Iranian defence attaché, called Israel`s attack a `gross miscalculation`.He saidIsraelileadersassumed the Iranian regime would collapse rapidly after the killing of key military and nuclearfigures. `They believed there would be political chaos and potential defections.

He said the attacks were a `regime change effort` as demonstrated by Israeli Prime Minister Benjamin Netanyahu`s address on June 14 where he addressed the Iranian people directly, attempting to `incite internal dissent`.

However, these efforts `failed`, Mr Shahabi said, adding Tehran quickly filled the leadership vacuum created by the killing of top soldiers and initiated self-defence through missile strikes. He said Israeli attacks extended far beyond military targets, hitting civilian, academic, industrial, residential, and cultural sites, including Evin Prison, hospitals, and a state broadcaster.

At least 1,100 persons, including 56 children, were killed in these attacks, according to the Iranian official.

He added that Iran, in response, targetedIsraeli military and security sites, while any civilian casualties were `likely collateral damage from Israel`s defence systems` which intercepted incoming Israeli missiles.

Mr Shahabi also talked about Iranian strikes on US bases and said the Al-Udeid air base in Qatar was chosen since it was `far away from civilian populations and cities`.

Negotiation `cover for attack` He called the US and Israeli attacks a violation of the UN Charter and the principles of the Nuclear Non-Proliferation Treaty.

The Iranian defence attaché also slammed Western nations for `diplomatic betrayal`, stating negotiations were ongoing when Israel launched its strikes.

The US negotiations with Iran were a `facade` to prepare for military escalation.

He said Israeli PM Netanyahu confirmed the operations were fully coordinated withWashington, contradicting US claims of diplomatic engagement.

US assessment Meanwhile, according to NBC, US officials believe the attack on Iran`s Fordow nuclear facilitywas successfulin settingback enrichment capabilities there by as much as two years. The report, citing two current officials, said the two other facilities struck by the US were not as badly damaged and may have been degraded only to a point where nuclear enrichment could resume in the next several months if Iran wants it to.

Reuters could not immediately verify the NBC report.

White House spokesperson Anna Kelly told Reuters in an emailed statement: `As the President has said and experts have verified, Operation Midnight Hammer totally obliterated Iran`s nuclear capabilities.

The chief Pentagon spokesperson SeanParnell told NBC that US President Donald Trump `was clear and the American people understand: Iran`s nuclear facilities in Fordow, Isfahan, and Natanz were completely and totally obliterated. There is no doubt about that.

The US launched strikes on Iran`s nuclear facilities last month, saying that they were part of a programme geared towards developing nuclear weapons.

Tehran maintains that its nuclear development is purely for civilian purposes.

A preliminary assessment in June from the Defence Intelligence Agency suggested that the strikes may have only set back Iran`s nuclear program by months. But Trump administration officials said that assessment was low confidence and had been overtaken by intelligence showing Iran`s nuclear programme was severely damaged.

With input from Reuters