Bulgarian prosecutors have charged seven people with membership of a criminal group preaching radical Islam and propagating war, local media reported on Wednesday.

The group, which was found to have propagated ideas relating to Islamic State organisation, comprised Bulgarian nationals of Roma origin who used Arab names to communicate among themselves.

Imam Ahmed Musa Ahmed, a Muslim spiritual leader in the Roma neighbourhood of the city of Pazardhik, was the group’s chief, according to the prosecution.

Earlier on Wednesday, prosecutors formally charged Ahmed Musa Ahmed with membership of a group propagating war and anti-democratic ideology.The imam has rejected the charges, according to his defence lawyer Elvira Penkova.

The group was arrested during a large-scale operation against extolling the ideology of Islamic State. The operation was conducted by the State Agency for National Security, or DANS, under the supervision of the Chief Prosecutor's Office on Tuesday and Wednesday.

DANS Chairman Vladimir Pisanchev told a press briefing the group “isn’t an Islamic State cell but it could have been one”.

According to Pisanchev, the investigation has found out that members of the group were allegedly attempting to recruit fighters for Islamic State. Islamist jihadists had used the homes of group members as transit points, Pisanchev added.

The operation is part of an investigation of suspected “propagation of a fascist or another anti-democratic ideology or a forced change of public and state order established by the Constitution” and “propagation of war”. Both crimes carry jail terms or fines under Bulgaria's Penal Code.

Imam Ahmed Musa Ahmed is appealing an earlier four-year jail sentence he had been issued for propagating radical Islam ideology.