Islamic State (Isis) militants are reportedly covering the streets of Raqqa in Syria with sheets to protect themselves from drone strikes. Activists from inside Raqqa have posted images of sheets laid across the top of homes and shops in the city, noting that this was Isis' way of protecting their fighters from the US-led coalition.

The images were posted by the activist group "Raqqa is Silently Being Slaughtered" on their Twitter page on 27 April, drawing comments from a number of people across social media. While some responded by saying it was a smart technique, others were quick to dismiss it by saying that drones could "see through" the sheets.

Meanwhile, Colonel Steven Warren, spokesperson for the US-led coalition in Syria, told Newsweek: "They've been using this tactic for a year. Extensive use in Ramadi but also everywhere else. They also use tunnels."

The activist group that posted the images are one of the only campaign groups working inside Syria. They call themselves the "Syrian campaign against Isis" and often post news, images and information about the way Isis terrorists are operating in the region. In April they were nominated for Citizen Journalism award by the Best of Online Activism.

Isis has also commanded residents of Raqqa to assist with creating the makeshift cover for the city's streets. The terror group has also demanded a payment from residents to fund the temporary shield.

According to the Telegraph, an Isis commander sent a letter to all residents stating: "We are all partners, which means every house must pay 2,000 Syrian pounds (£6) for installation of the sheets, which we began putting days ago in some of the main streets in order to prevent aerial spying on its fighters."