It's been announced in Iran that a number of employees of the Intelligence Ministry are among a group of people arrested in connection with the killing of Iranian liberal writers and activists late last year.

The ministry said that their actions amounted to treason.

The BBC Middle East correspondent says that the series of abductions and murders were widely seen as the latest of many attempts by hardline conservatives to suppress the movement for change.

A reformist newspaper, whose revelations triggered the admission, is demanding that those higher up the chain of command at the ministry should also be punished.