The declaration, due to be issued after a two-day summit of the 56-member Organisation of Islamic Co-operation (OIC) in Cairo starting today, does not mention President Bashar al Assad and pins most of the blame on his Government.
The text discussed by foreign ministers at a preparatory meeting yesterday came after Syrian opposition leader Moaz Alkhatib offered to meet Mr Assad's deputy to negotiate a way to end the bloodshed, in which the United Nations says at least 60,000 people have died.
The draft statement said: "We strongly condemn the ongoing bloodshed in Syria and underline the Syrian government's primary responsibility for the continued violence and destruction of property.
"We express grave concern over the deteriorating situation, the increasing frequency of killing which claims the lives of thousands of unarmed civilians and the perpetration of massacres in towns and villages by the Syrian authorities."
It was not clear whether Syria's ally Iran, which is attending the OIC summit, would back the tough wording.
However, Mr Alkhatib, leader of the Syrian National Coalition, made his offer of talks after ground-breaking meetings with the foreign ministers of Russia and Iran, Mr Assad's two main allies, at a security conference in Germany.
The OIC suspended Syria's membership last August, citing Mr Assad's violent suppression of the revolt.
The summit draft called on Syrian opposition forces to speed up the formation of a transitional government "and to be ready to assume the political responsibility in full until the completion of the desired political change process".
It added: "We urge the Syrian regime to show wisdom and call for serious dialogue to take place between the national coalition of the Syrian revolution, opposition forces, and representatives of the Syrian Government committed to political transformation in Syria and those who have not been directly involved in any form of oppression."
A Syrian opposition source said the Syrian National Coalition had not been invited to the summit and would not be present, although Mr Alkhatib's headquarters is in Cairo.
Mr Alkhatib urged Mr Assad on Monday to respond to his initiative for dialogue, saying it was aimed at ending the bloodshed and helping the regime leave peacefully.
Speaking after meeting senior Russian, US and Iranian officials, he said none of them had a plan to end the civil war and Syrians must find their own resolution.
He said: "The big powers have no vision. Only the Syrian people can decide on the solution."
The moderate Islamist preacher announced last week he was prepared to talk to Mr Assad's representatives.
Although he set conditions, the move broke a taboo on contacts with authorities and dismayed many in opposition ranks who insist on Mr Assad's departure as a precondition for negotiation.
Mr Assad announced last month his plans for reconciliation talks to end the violence but – in a speech described by UN Syria envoy Lakhdar Brahimi as narrow and uncompromising – he said there would be no dialogue with people he called traitors or "puppets made by the West".
Syria's uprising erupted 22 months ago with largely peaceful protests, escalating into a civil war that pits mainly Sunni Muslim rebels against Mr Assad, who is from Syria's Alawite minority.