Iran has designated the United Kingdom's Royal Navy and Royal Air Force as terrorist organisations, while classifying Britain's foreign intelligence service MI6 as a hostile group.

The decision was announced in a statement issued by Iran's Foreign Ministry on November 1.

According to the statement, under Iran's law on tightening penalties for espionage and cooperation with countries acting against the country's national interests and security, MI6 is classified as a "hostile group", with the relevant legal provisions applying to the British intelligence agency.

"In a reciprocal response to the United States' designation of the Islamic Revolutionary Guard Corps (IRGC) as a terrorist organisation, the Royal Navy and the Royal Air Force of the United Kingdom are recognised as terrorist organisations as of the publication of this statement," the ministry said.

The statement added that the measures had been taken in accordance with international law and the principle of reciprocity, warning that the other party would be responsible for any negative consequences arising from the decision.

The Foreign Ministry said the move followed a decision by Iran's Supreme National Security Council in response to what Tehran described as Britain's anti-Iranian actions over the past year.