The World Council of Churches (WCC) has repeated its call for the release of two archbishops abducted in Syria five years ago.

Syriac Orthodox Archbishop Yohanna Ibrahim and Greek Orthodox Archbishop Paul Yazigi were kidnapped at gunpoint outside Aleppo in April 2013 and haven't been seen since. 

No extremist groups have claimed responsibility for the kidnappings or demanded ransoms, and the fate of the pair remains unknown. 

The WCC called for the safe return of the two church leaders in June this year and has reiterated the call after the 2,000-day mark since the kidnapping was passed last week. 

WCC general secretary Rev Dr Olav Fykse Tveit said: 'Sadly, the statement issued by the WCC Central Committee at its bi-annual meeting in June this year calling for a safe return of our Christian brothers to their churches, their communities and their families, needs to be repeated. We continue to pray for them, as a sign of hope for all the Christians of Syria and the region.'

The WCC voiced concerns over the continued conflict in Syria as well as deteriorating conditions for Christians across the Middle East. 

'As Christian witnesses, we will continue to stand by victims of war and injustice, and cry out loud against human rights violations,' Tveit affirms.

The Russian Defence Ministry claimed this week that ISIS attacked a refugee camp in Syria's Deir ez-Zor province and took 700 people hostage.  Vladimir Putin said the terrorist group had threatened to execute 10 a day unless its demands were met. 

'They have issued ultimatums, specific demands and warned that if these ultimatums are not met they will execute ten people every day.

'The day before yesterday they executed ten people,' Putin said, according to to the Daily Mail, adding: 'This is just horrible, it is a catastrophe.'

The Britain-based Syrian Observatory for Human Rights told the newspaper that ISIS wants medicine and food in exchange for the release of the hostages.