Iranian authorities have denied reports circulating on social media that President Masoud Pezeshkian has been killed, Tabnak reported on February 28.

A senior official contacted by Shafaqna news agency denied the rumours, calling them false, Tabnak reported. No further details on Pezeshkian's whereabouts or condition were provided.

The denial came as Israeli and US forces struck Tehran earlier on February 28, with the first blasts heard near the compound of Supreme Leader Ayatollah Ali Khamenei in downtown Tehran at around 9:45am local time. Roads to the compound had already been shut down by authorities before the strikes began.

Israeli Defence Minister Israel Katz confirmed the attack, describing it as pre-emptive. "Israel has launched an attack against Iran," he said, without elaborating on targets or scale. 

Further explosions were heard in northern and eastern Tehran, as well as in the cities of Isfahan and Qom, according to Eqtesad News. Witnesses described shop and residential windows blown out along Vasal Street and the intersection of Enghelab Avenue, with BRT lane barriers torn from the ground, indicating the scale of the blasts.

Some reports indicated missile strikes near University Street and the Republic area of central Tehran.

The United States confirmed its participation in the operation. The New York Times cited a US official confirming that American strikes against the Islamic Republic had begun, while AP reported the involvement of a US official and a person familiar with the operation who spoke on condition of anonymity.

Iran's Civil Aviation Organisation closed the country's entire airspace until further notice on the basis of a NOTAM, while mobile phone services were cut across the capital. Sirens sounded across Israel simultaneously, with the Israeli military issuing a proactive alert warning the public of the possibility of retaliatory missile launches.

It was not immediately clear whether Khamenei had been present in his offices at the time of the first strike. He had not been seen publicly in days as tensions with Washington mounted over Iran's nuclear programme. Iran had previously warned that American military personnel and bases across the region would be considered legitimate targets in any retaliation.

No official casualty figures had been released at the time of publication.

This story is developing.