Iranian state television has broadcast emergency instructions advising the public on how to protect themselves in the event of a nuclear strike.

The guidance urges people not to look at the flash of an explosion, to take cover behind a solid barrier, lie face down and protect their heads and faces, according to rbc.ru.

Once the blast wave has passed, people are advised to enter the nearest building and stay away from windows and exterior walls. Authorities also warn against remaining outdoors to watch an explosion or record it on a mobile phone.

The broadcast also outlined precautions in the event of radioactive contamination. People are advised to remove their outer clothing without shaking off dust, place it in a sealed bag and take a warm shower with soap and water.

If showering is impossible, exposed skin should be cleaned with water or wet wipes.

Indoors, residents are advised to close windows and doors, switch off ventilation systems and use bottled water and food in sealed packaging. People should remain in shelters for at least 24 hours and leave only when instructed by authorities.

The broadcast comes amid speculation about a possible US nuclear strike against Iran.

On November 2, journalist Tucker Carlson claimed that US President Donald Trump's administration could consider using nuclear weapons against Iran under pressure from Israeli Prime Minister Benjamin Netanyahu. Carlson suggested that a decision could be made before November 7.

He identified an underground facility inside Mount Kolang-Gaz La, near Natanz, as a possible target. Carlson said that Israeli intelligence believes Tehran has resumed uranium enrichment at the site.

The facility is reportedly located about 100 metres underground and is beyond the reach of even US bunker-buster bombs, Carlson claimed.

However, the White House said that Carlson had no information about the administration's military plans.

Trump also ruled out using tactical nuclear weapons against Iran.

At the same time, Trump left open the possibility of further strikes against Iran's fortified underground facilities.