Reports from Turkey claim that hundreds of Islamic State (Isis) supporters were able to hold Eid prayers openly inside Istanbul.

Turkish media reports said on Sunday that around 1,000 Isis members had gathered at a picnic site in Omerli neighbourhood in Istanbul to perform Eid prayers on July 17.

Isis, which adheres to strict Salafist practices, had asked its followers to avoid attending Eid al-Fitr prayers in mosques not controlled by the group. 

The Eid prayers were reportedly attended by several high-ranking Isis members, who severely criticised the Turkish government and asked its followers to 'wage war' to take back the country from the infidels.

Sputnik Turkiye reported that top Isis leaders Halis Bayancuk, who also goes by the name of Abu Hanzala gave a sermon following the prayers. In his 14-minute address to the gathering, Bayancuk reportedly asked the followers to wage a war against the Turkish government, as it was needlessly arresting Isis supporters in Turkey.

As per reports, this is the second time Isis has held a mass gathering inside Turkey. The incident has caused an outcry inside Turkey, following which local authorities claimed that the police were not notified of the public gathering.

The meeting was illegally held as there was no clearance obtained to conduct it on a public property, according to local reports.