Christians are praying amid uncertainty over the whereabouts of two senior church figures kidnapped in Syria.

Bishop Paul Yazigi of the Antiochian Orthodox Church and Bishop John Ibrahim of the Syriac Orthodox Church were kidnapped at gunpoint on Monday. Their driver was killed.

Early media reports stating that the two men had been released have not been confirmed.

Today, the Universal Syriac Orthodox Church posted an Apostolic Instruction on its Facebook page from Patriarch Moran Mor Ignatius Zakka asking all Syriac Orthodox churches to offer "special prayers" for the bishops.

In a separate post today, it urged members to sign a White House petition started by Syrian Christians living in the US.  The petition urges the US government to intervene to secure the release of the two church leaders.

In a joint statement, the patriarchs of the Greek Orthodox and Syriac Orthodox churches called on churches around the world to "stand fast in the face of what is going on and witness to their faith in the power of love in this world".

"The Christians in this East are deeply sorrowed by what their countries are going through, namely violence that is spreading and killing the sons of the one country and exposing their lives to various dangers of which kidnapping, that represents one of its the most horrible expressions due to its absurdity, and is jeopardising of the lives of the peaceful and unarmed individuals," they said.

"We call the kidnappers to respect the life of the two kidnapped brothers as well as everyone to put an end to all the acts that create confessional and sectarian schisms among the sons of the one country.

"We understand the anxiousness of the Christians because of what happened and call them to patience, to hold on to the teachings of their faith, and to rely on God whose strength lies in our weakness."

They added: "In this painful situation, we can but call the whole world to try putting an end to the Syrian crisis so that Syria becomes again a garden of love, security and coexistence.

"Settling accounts should not happen at the expense of the human beings who live here."

Christian Solidarity Worldwide's Chief Executive Mervyn Thomas said, "CSW is deeply concerned by these kidnappings and our thoughts and prayers are with both men and also with Syrian Christians, who must be deeply disturbed and discouraged by these developments.

"We urge key members of the international community, and particularly those belonging to the 'Friends of Syria' group, to make urgent representations to ensure these men are released swiftly and unharmed, and to encourage every party to the conflict to adhere to humanitarian standards with regard to the treatment of civilians, religious leaders and religious establishments, regardless of creed or ethnicity."