Jihadists claiming to be 'Islamic State in Central Africa' have called for militants to join them in the Democratic Republic of the Congo after the extremist group's self-styled 'capital', Raqqa, was reclaimed by US-backed Syrian forces.

A video circulating on pro-ISIS sites purports to be a message from dedicated jihadis, although ISIS has not expanded its official media output to the central African country.

In the footage, a man brandishing a gun and with bullets draped around his neck addresses the camera in Arabic as other men and some children are seen standing behind him.

He says: 'I swear to God that this is Dar al Islam of the Islamic State in Central Africa,' according to a translation by PJ Media.

His two-minute-long statement is punctuated several times by members of the crowd behind him shouting 'Allahu Akbar', or 'Allah is greatest'.

The clip is branded with the ISIS logo as well as the letters MTM - a suggestion of what the Congolese group calls itself.

Although ISIS affiliates have a strong presence in the north African countries of Libya and Egypt, the video is the first suggestion that its influence has spread to the Congo.

The central African country is predominantly Christian with only 1.6 per cent of the population identifying as Muslim in 2010, according to the Encyclopedia Britannica.

Call to arms: A video (above) circulating on extremist sites purports to be a message from dedicated Islamic State fighters in the Congo, although ISIS has not expanded its official media output to the central African country

Passionate: In the footage, a man brandishing a gun and with bullets draped around his neck addresses the camera in Arabic as other men and some children are seen standing behind him

Terrorist organisations whose reach extends closer to the Congo than ISIS' include Boko Haram in Nigeria and Al-Shabaab in Somalia.

ISIS' hold over the Middle East is gradually crumbling, with Raqqa in Syria being liberated by US-backed troops yesterday. But the conflict has come at a devastating cost to both Syria and Iraq, with immense suffering for those who endured the militants' brutal reign.

The nine-month battle to liberate Mosul resulted in the death of up to 1,500 Iraqi forces, while at least 1,100 fighters in the Syrian Democratic Forces fighters were killed in the battles for Raqqa and Deir el-Zour up until late September, according to the coalition.

In the three years since ISIS began building its 'caliphate,' it has killed thousands of people, displaced millions and indoctrinated countless children with its extremist beliefs.

He says: 'I swear to God that this is Dar al Islam of the Islamic State in Central Africa'