Iran's armed forces threatened on Saturday to destroy US-linked oil infrastructure after President Donald Trump said the United States had bombed Iran's oil hub Kharg Island.

The military's Al-Anbiya Central Headquarters said in a statement cited by Iranian media that oil and energy infrastructure belonging to firms that cooperated with the United States would "immediately be destroyed and turned into a pile of ashes" if Iran's energy facilities were attacked.

The announcement, reported by Iran's Fars and Tasnim news agencies, was in "response to statements" made by the US president who had earlier said in a social media post that strikes had "obliterated" military targets on Kharg Island.

Trump had also threatened to hit the island's oil infrastructure if Tehran did not allow passage for ships via the strategic Strait of Hormuz, through which a fifth of global crude oil and liquefied natural gas normally pass.

Kharg Island, located around 30 kilometres (19 miles) off the Iranian mainland, handles roughly 90 percent of Iran's crude exports, according to a recent JP Morgan note.

The war has sparked chaos in global markets and sent oil prices soaring.

Iranian strikes have all but halted maritime traffic in the Strait of Hormuz, leaving investors and governments globally nervous about the risk of dwindling energy supply and higher inflation.