Iran launched a \"sophisticated cyber-attack\" in an attempt to disrupt the BBC\'s Persian service, which is watched by over seven million viewers weekly, the broadcaster\'s chief was to claim Wednesday. Director-general Mark Thompson is expected to use Wednesday\'s address to the Royal Television Society to accuse Iran of trying to \"undermine\" the popular service, according to extracts from the speech released by the BBC. \"There was a day recently when there was a simultaneous attempt to jam two different satellite feeds of BBC Persian into Iran, to disrupt the service\'s London phone lines by the use of multiple automatic calls, and a sophisticated cyber-attack,\" the British broadcaster\'s chief will say. \"It is difficult, and may prove impossible, to confirm the source of these attacks, though attempted jamming of BBC services into Iran is nothing new and we regard the coincidence of these different attacks as self-evidently suspicious.\" The BBC announced recently that Persian TV had doubled its audience from 3.9 million weekly viewers in 2009 to nearly 7.2 million. \"More than one in 10 Iranians now watch BBC Persian TV each week,\" said the BBC, which has previously accused Iran of attempting to jam its broadcasts and intimidate staff working for the London-based service.