DUBAI (Reuters) - Iranian Supreme Leader Ayatollah Ali Khamenei condemned Britain on Saturday as a “source of evil and misery” for the Middle East after British Prime Minister Theresa May called Iran a regional threat.

Iran's Supreme Leader Ayatollah Ali Khamenei waves as he gives a speech on Iran's late leader Khomeini's death anniversary, in Tehran, Iran June 3, 2016. Leader.ir/Handout via REUTERS

“Shamelessly, the British have recently called ... Iran a threat to the region, but everyone knows that ... it is the British who have always been the source of threats, corruption and misery,” the state news agency IRNA quoted Khamenei as telling participants at an Islamic unity conference in Tehran.

Khamenei called “policies and the actions of the British in the past two centuries a source of evil and misery for the peoples of the region”, IRNA added.

May called on Gulf Arab heads of state at a summit last week to work with London “to push back against Iran’s aggressive regional actions, whether in Lebanon, Iraq, Yemen, Syria or in the Gulf itself”.

“So I want to assure you that I am clear-eyed about the threat that Iran poses to the Gulf and the wider Middle East,” she told the summit in Bahrain on Dec. 7.

Khamenei accused the United States and Britain of provoking conflicts among the main Sunni and Shi’ite branches of Islam and said: “The old British policy of ‘divide and conquer’ is seriously on the agenda of Islam’s enemies.”

Iranian media reported on Saturday that the foreign ministry had summoned a top British diplomat in Tehran to protest against British criticism of its actions in Syria.

The move came after British Foreign Secretary Boris Johnson said on Thursday he had summoned the ambassadors of Russia and Iran to convey his “profound disquiet” over events in the besieged Syrian city of Aleppo. [U8N19K021]

Britain and Iran exchanged ambassadors in September more than a year after Britain reopened its Tehran embassy, which was closed for nearly four years after it was stormed by protesters.

Iran and most Gulf states are on opposite sides in Middle East conflicts, with Iran an ally of President Bashar al-Assad in Syria’s civil war and of the armed Houthi movement fighting a Saudi-led military coalition in Yemen.