TEHRAN (Reuters) -- Authorities in Tehran say they have detained eight local British embassy staff, underscoring the hardline leadership's effort to blame post-election unrest on foreign powers, not popular anger.
Britain called the arrests "harassment and intimidation" and demanded the release of the embassy employees.
Supreme Leader Ayatollah Ali Khamenei denounced what he called "interfering statements" by Western officials following Iran's disputed presidential election, state media reported.
"If the (Iranian) nation and officials are unanimous and united, then the temptations of international ill-wishers and interfering and cruel politicians would no longer have an impact," state radio quoted Khamenei as saying.
Khamenei on June 19 called Britain the "most treacherous" of Iran's enemies which he accused of orchestrating an unprecedented outpouring of protest after the June 12 poll.
"Eight local employees at the British embassy who had a considerable role in recent unrest were taken into custody," the semi-official Fars news agency reported on June 28, without saying when the detentions took place.
The authorities, while taking tough action to snuff out any embers of protest, have repeatedly accused Britain and the United States of inciting the turmoil. Both countries deny it.
"This is harassment and intimidation of a kind that is quite unacceptable," British Foreign Secretary David Miliband told reporters at an international conference in Corfu.
"We want to see (the embassy staff) released unharmed."
The detentions will further strain ties between London and Tehran, who have already expelled two of each other's diplomats since the election sparked the gravest internal challenge to the Iranian authorities since the 1979 Islamic revolution.
The streets of Tehran have sunk back into a sullen calm after riot police and religious basij militia crushed huge demonstrations in which at least 20 people were killed.
Official results showing hardline President Mahmoud Ahmadinejad won re-election by a landslide were met with disbelief by many Iranians who agreed with complaints by the
runner-up, Mirhossein Mousavi, that the vote was rigged.
Mousavi has repeated demands for the election to be rerun, in defiance of Khamenei who declared the poll fair, but he appears to have dwindling options for any further challenge.
The Guardian Council, Iran's top legislative body, is to give its final verdict on the election by Monday. The 12-man body has offered a partial recount -- rejected by Mousavi and fellow-candidate Mehdi Karoubi -- but it has already described the poll as the healthiest since the revolution.
British Prime Minister Gordon Brown has condemned violence and media censorship in Iran since the election. Britain suspended its diplomatic ties with Iran after the Islamic revolution in 1979, only reopening an embassy in 1988, following the Iran-Iraq war. Full normalization only took place in 1998.