Activities of oil companies "at this export terminal are continuing as normal", said Ehsan Jahaniyan, deputy governor of Iran's southern Bushehr province, quoted by the IRNA news agency.

The Fars news agency, citing sources on the island, earlier reported there had been no damage to oil facilities after President Donald Trump said US strikes had destroyed only military targets.

Trump had threatened to target oil infrastructure on the island, a crucial hub for Iran, if Tehran continues to block the strategic Strait of Hormuz.

Iran has, in turn, threatened to target US-linked oil infrastructure.

Deputy governor Jahaniyan said that after the attacks "daily life and routine activities of the residents are also fully maintained."

The attack "did not cause any casualties among military personnel, company employees, or residents of Kharg island, he added.

According to Fars, the US operation "tried to damage the army's defences, the Joshan naval base, the airport control tower and the helicopter hangar of the Iran Continental Shelf Oil Company."

Kharg Island, a scrubby stretch of land in the northern Gulf around 30 kilometres (19 miles) off the Iranian mainland, handles roughly 90 percent of Iran's crude exports.