Iran's Supreme National Security Council issued its first official statement on February 28 confirming that the country's armed forces had begun a retaliatory response to the joint US-Israeli strikes, IRNA reported.

"The armed forces of the Islamic Republic of Iran have begun a crushing response to the enemy's wicked actions," the council said in a statement, adding that the population would be kept continuously informed of developments.

The council described the strikes as having taken place while nuclear negotiations were under way, saying the enemy believed "the steadfast Iranian nation would surrender to their lowly demands through these cowardly actions."

In a series of practical directives, the council told citizens in Tehran and other targeted cities to travel to other cities or areas where possible while maintaining calm, warning that operations by the two countries were expected to continue across Tehran and other urban centres.

Schools and universities were closed until further notice. Government offices were ordered to operate at 50% capacity. Banks were said to remain open and operational.

The council said the government had made advance preparations to ensure supplies of essential goods and urged the public to avoid crowding in shopping centres due to potential safety risks.

"There is no cause for concern regarding the provision of public necessities," the statement said.

The council said further updates would follow.

The statement came as explosions continued across Tehran, Isfahan and Qom, with Iran's airspace closed, internet connectivity at 4% of normal levels according to NetBlocks, and the rial at a record low of IRR1,749,500 against the dollar.

Explosions had also been reported in Abu Dhabi and reports circulated of strikes on the US Fifth Fleet headquarters in Bahrain as well as Dubai and Saudi Arabia in recent minutes.

This story is developing. Details remain unverified and subject to change.