LONDON -- The British government says all diplomats form the Iranian embassy have left the country.

The Foreign Office says the diplomats left Heathrow airport on a chartered plane on Friday afternoon.

They were expelled by the government in retaliation for attacks on the British Embassy in Tehran.

Tehran's relations with Britain have become increasingly strained in recent months, largely due to tensions over Tehran's refusal to halt uranium enrichment -- a process that can lead to the development of nuclear weapons.

The roughly two dozen Iranian diplomats and their dependents will be welcomed back at the Tehran airport, Iran's semiofficial Fars news agency reported.

Images broadcast around the world Tuesday showed demonstrators tearing down Union Jack flags and brandishing a looted picture of Queen Elizabeth II at the U.K. embassy compound in Tehran. The incident has deepened Iran's isolation and significantly escalated tensions with the West.

Foreign Secretary William Hague also pulled Britain's diplomats out of Iran following the embassy attack, and backed new sanctions on the Islamic republic. At least four other European countries, including Germany and France, also moved to reduce diplomatic contacts with Iran.

Hague has said the attacks were "clearly premeditated" by high-ranking officials, but claimed there were "divisions within the Iranian regime" about the move.

Iran's government has criticized the attacks, but hard-liners have spoken out in support of the protesters. Mohammad Mohammadian, a representative of Supreme Leader Ayatollah Ali Khamenei, praised the attackers, saying they had targeted the "epicenter of sedition."