A charity supporting persecuted Christians worldwide has reported that despite US President Obama's claims that Islamic extremist group al-Qaeda has been "decimated", it is in fact merely operating under a different name and is even "expanding" its territory within the Middle East.

Dr Patrick Sookhdeo, international director of Barnabas Fund, says that one al-Qaeda-linked terrorist group, The Islamic State of Iraq and Levant (ISIS, or ISIL), has gained control of a significant amount of land in northern Syria.

ISIS is hoping to establish a cross-border Islamic state in the Middle East and is capitalising on the devastating conflicts that are currently ongoing in the region. A spokesperson for the militant group, which is made up of Sunni Muslims, last week declared war on Shiites in Iraq, Lebanon and Yemen.

Its hold is weaker now than it was between 2004 and 2007, but Dr Sookhdeo notes that ISIS has "recently reclaimed vast swathes" of Iraq, and 2013 marked its most violent year since 2008. An estimated 7,000 were killed, double the number in 2003, which has raised fears that a civil war will ensue.

The persecution of Christians throughout the region has led to a mass exodus of those of the faith, despite their deep roots and heritage in the Middle East.

Barnabas says believers have been "deliberately and mercilessly targeted by Islamist militants", leading to a UN estimation that 850,000 Christians have fled Iraq since 2003. The escalation of human rights abuses and the destruction of church buildings have led Barnabas to label ISIS's actions as "a form of ethnic cleansing".

ISIS is also fighting to impose a strict Islamic state in Syria, though Barnabas notes that this is not supported by the local people. However, "ominously, this has not diminished their influence in the country".

Due to this lack of support, it is highly unlikely that ISIS will ultimately succeed in their endeavours, but it will certainly continue to cause horrific devastation and further casualties, "ensuring a threat to the prospect of peace in the region and to the future of the diminishing Christian community," say Barnabas.

Aid agencies and charities are calling upon delegates at the Geneva II conference next week to address ISIS's wider aspirations and take active steps to stop them from causing further damage to the stability of the Middle Eastern region.

Dr Sookhdeo said: "Contrary to President Obama's repeated statements that the Islamists have been been 'decimated' and are 'on the path to defeat', al-Qaeda is alive and kicking, even extending their territory."