Iran was "unsuccessful" in targeting the joint UK-US Indian Ocean military base at Diego Garcia, a UK official source confirmed to AFP on Saturday, after the Wall Street Journal reported Tehran fired two ballistic missiles at it.

Diego Garcia, which is around 2,500 miles (4,000 kilometres) from Iranian territory, is one of the two bases the UK has allowed the United States to use for "defensive operations" in its war against Iran.

On Friday, the UK government said it would allow Washington to use its bases in Diego Garcia and Fairford in southwest England to target Iranian "missile sites and capabilities being used to attack ships in the Strait of Hormuz".

The UK official source confirmed that Iran's "unsuccessful targeting of Diego Garcia" took place before Friday's announcement.

The source did not confirm additional details about the attack.