The whistleblowing website WikiLeaks says it plans to release a secret military video of one of the deadliest US air strikes in Afghanistan in which scores of children are believed to have been killed. It said it fears it is under attack after the US authorities said they were searching for the site's founder, Julian Assange, following the arrest of a US soldier accused of leaking the Afghanistan video and another of a US attack in Baghdad in which civilians were killed. It says it is still working to prepare the film of the bombing of the Afghan village of Garani in May 2009. The video could prove to be extremely embarrassing to the US military. The US ... used weapons that create casualties over a wide area, including one-tonne bombs and others that burst in the air. But two US military officials told a newspaper last year that no one checked to see whether there were women and children in the buildings. In an email to supporters, Assange said WikiLeaks has the Garani video and "a lot of other material that exposes human rights abuses by the US government". In his email, Assange also calls on supporters to protect the website from "attack" by the authorities following the detention of a US soldier, Bradley Manning, who was arrested in Iraq after admitting to a former hacker that he leaked the Garani and Baghdad videos to WikiLeaks.