Activists behind a website dedicated to revealing secret documents have complained of harassment by police and intelligence services as they prepare to release a video showing an American attack in which 97 civilians were killed in Afghanistan. Julian Assange, one of the founders of Wikileaks, has claimed that a restaurant where the group met in Reykjavic, the capital of Iceland, came under surveillance in March and one of the groups volunteers was detained for 21 hours by police. Assange, an Australian, says he was followed on a flight from Reykjavik to Copenhagen by two American agents. The group has riled governments by publishing documents leaked by whistleblowers. Last week it released the cockpit recording from an American Apache helicopter as it killed Iraqi civilians, including a Reuters photographer, in Baghdad in 2007. Assange claims surveillance has intensified as he and his colleagues prepare to put out their Afghan film. It is said to concern the so-called Granai massacre, when American aircraft dropped 500lb and 1,000lb bombs on a suspected militant compound in Farah province on May 4 last year. Several children were among those killed. In messages on Twitter, the internet social networking site, Assange complained of covert following and hidden photography by police and foreign intelligence services. There have been thinly veiled threats, he says, from an apparent British intelligence agent in a car park in Luxembourg. Computers were also seized, another member of Wikileaks said on Twitter, raising alarm among supporters with a subsequent post: If anything happens to us, you know why ... and you know who is responsible. Their apprehension is perhaps understandable. Americas defence establishment has made clear that it would like to silence the site. In 2008, the Pentagon produced a report on how to undermine and neutralise Wikileaks. This, too, emerged on the website. Assange, who is believed to be 37, founded Wikileaks three years ago with a group of like-minded computer programmers, academics and activists. The site says it has had more scoops since then than The Washington Post in three decades and has become a global clearing house for sensitive documents. It has exposed crimes from toxic dumping and tax evasion to extrajudicial murders in Kenya. Assange says the 38-minute Iraqi video broadcast by the group is evidence of collateral murder by American forces. It shows a group of Iraqi men being killed by gunfire from the helicopter. A helicopter then shoots at a van arriving to take the bodies away. A crew member is heard saying: Nice shooting. When it emerges that two children in the van have been injured, someone else says: Serves them right for bringing their children into a battle. The film, in which American forces kill with the seeming detachment of video gamers, has been seen by millions on the internet since it was first aired on Monday. The website, which claims to exist on a shoestring budget, says it has since received more than 100,000 in donations. Americas military defended the killings, saying no disciplinary action had been taken at the time of the incident. However, Reuters has striven in vain since 2007 to obtain access to the video under freedom of information laws. Broadcasting such a film could expose Wikileaks to prosecution in America but the organisation appears to have put itself beyond the reach of court injunctions by existing only in the digital sphere. There has been speculation that Wikileaks might be part of a sophisticated psy-ops campaign by the CIA. If that is the case, says Assange, I only wish they would step forward with a cheque. Net Pimpernel leaks it here, leaks it there, Profile, page 19. (The Sunday Times)