Iranian supreme leader Ayatollah Ali Khamenei said on Thursday Tehran must remain alert to what he called US and British plots against the Islamic republic.
"The British government, with its 200-year black record against Iran, and the United States and some others praise the actions of some people (opposition groups) and say 'we support Iranians,'" state television quoted him as telling the Assembly of Experts, which selects the supreme leader and supervises his activities.
"Therefore, we must not overlook the plots of enemies aimed at creating divisions among us," he said, without elaborating.
Khamenei also said the United States and Britain were "cheered" by some of the incidents after the June presidential election that saw Mahmound Ahmadinjejad reelected amid widspread claims of fraud.
In particular, Khamenei and other officials have lashed out at Britain since the election, accusing London of fomenting violence that rocked Tehran.
Tension between Iran and Western powers has heightened ahead of October 1 talks between the two groups over Tehran's controversial nuclear programme.
Tehran denies Western charges that its atomic programme is aimed at making nuclear weapons.