Iranian state media is reporting that authorities have released some members of the British Embassy staff in Tehran, one day after eight Iranian staffers there were detained for alleged links to the nation's post-election unrest.

A report quotes the nation's intelligence minister, Qolam Hosein Mohseni-Ejei as saying Sunday it has proof that some British embassy employees collected news about the recent protests.

It is unclear how many staffers remain in custody. 

British Foreign Secretary David Miliband (file photo)

Earlier in the day, British Foreign Secretary David Miliband demanded their release, calling their detention an unacceptable form of harassment and intimidation. 

European Union foreign ministers Sunday vowed the EU will respond in a "strong and collective" manner to any harassment or intimidation of staff members at embassies in Iran.

Separately, the Associated Press reports that witnesses told AP that up to 3,000 people protested in north Tehran Sunday.  Unconfirmed witness reports describe violent clashes between police and demonstrators that left people injured. 

And Iranian state media report former Iranian President Akbar Hashemi Rafsanjani called on the government Sunday to thoroughly and fairly investigate defeated candidates' complaints about the disputed June 12 election.

The former president is one of Iran's most powerful figures.

Iran has imposed heavy restrictions on journalists, such as preventing international reporters from gathering news from the streets.  Authorities have arrested dozens of university professors, dissidents, journalists and citizens in the post-election crackdown.

The official death toll from the post-election violence stands at 17, but witnesses say it is much higher.

Also Sunday, Iran's Supreme Leader Ayatollah Ali Khamenei accused British and U.S. officials of making absurd comments about Iran.  

Tehran has accused both Britain and the United States of involvement in the street protests and violence that swept the country after its June 12 presidential election.

Some information for this report was provided by AP and Reuters.