The Islamic State (Daesh) has been killing its own fighters by the dozen – dissolving some in acid – and as it tries to root out spies and informants the group believe are directing air strikes.

The Associated Press reported that in recent months Isis leadership had killed dozens of their own members, in the wake of a series of successful drone strikes on high-profile figures.

Daesh has displayed the bodies of some of those it believes to be spies in public spaces or used particularly violent and ostentatious methods of execution including dissolving some in acid, reportedly until their organs were destroyed.

Paranoia is being fuelled among the ranks of the militant group and now the use of mobile phones or the internet can be enough to fuel suspicion. Rami Abdurrahman said a number of Isis fighters had begun feeding information about the whereabouts of their leaders to outsiders because of a loss of wages flowing the Russian intervention in Syria.

The extremist group cut the wages of its fighters earlier in the year following air strikes on Isis oil facilities.

According to experts, senior Daesh officials will not move from Iraq into Syria for fear of being killed in targeted strikes. Omar al-Shishani, Islamic State's Minister of War, the feared Iraqi militant Shaker Wuhayeb, also known as Abu Wahib, and a top finance official known by several names, including Haji Iman, Abu Alaa al-Afari or Abu Ali Al-Anbari have all been killed in recent strikes, according to the Associated Press.

The level of hysteria over the quickly diminishing ranks of top Isis officials now means that fighters have their phones inspected in spot checks and unrecognised numbers are called. After the killing of Abu Ali Al-Anbari, eight Islamic State officials were taken into custody in Mosul. They have since disappeared and their whereabouts is unknown.