* 56-nation group wants negotiated end to civil war
* Draft communique urges creation of transitional government
* Summit heightens profile of Egypt's Islamist president
* Tunisian shooting highlights fragility of "Arab Spring" (Adds remarks from Iranian FM, Syrian opposition leader)
By Shaimaa Fayed and Paul Taylor
CAIRO, Feb 6 (Reuters) - Leaders of Muslim nations called for a negotiated end to Syria's civil war at a summit in Cairo on Wednesday, thrusting Egypt's new Islamist president to centre stage amid turbulence at home.
On the summit sidelines, the leaders of Egypt, Turkey and Iran gathered for talks on the Syria crisis. The Iranian foreign minister came out of the meeting expressing optimism about the prospects for a resolution.
The head of the Syrian opposition, in Cairo but not at the summit, told BBC Arabic that Iran was making the decisions in Damascus, and gave the Syrian government until Sunday to release women detainees or else his offer of talks would lapse.
The summit of the 57-member Organisation of Islamic Cooperation opened on a day when the assassination of a leading Tunisian opposition politician highlighted the fragility of "Arab Spring" democratic revolutions in North Africa.
Tunisian President Moncef Marzouki cancelled his trip to the Cairo meeting after Shokri Belaid, a staunch secular opponent of the moderate Islamist government, was shot dead outside his home, triggering street protests.
With Mahmoud Ahmadinejad making an ice-breaking visit to Egypt, the first by an Iranian president since the 1979 Islamic revolution, the two-day meeting was focusing on how to stop the bloodshed in Syria, where President Bashar al-Assad counts Tehran as one of his last allies.
In a keynote address, Egyptian President Mohamed Mursi called on "the ruling regime" in Damascus to learn the lessons of history and not put its interests above those of the nation, saying that rulers who did so were inevitably finished.
Mursi urged all OIC members to support the Syrian opposition's efforts to unite and bring about change.
Heavy fighting erupted in Damascus on Wednesday as rebels launched an offensive against Assad's forces, breaking a lull in the conflict, opposition activists said.
Ahmadinejad earlier told Egyptian journalists there could be no military solution and he was encouraged that the Syrian government and opposition were moving towards negotiations to end a conflict in which at least 60,000 people have died.
His foreign minister, Ali Akbar Salehi, told Egypt's state news agency he believed the Syrian government was ready to negotiate with the opposition. "We are optimistic," he added after the meeting with the leaders of Turkey and Egypt.
OFFER OF TALKS
In an interview with BBC Arabic on Wednesday, opposition Syrian National Coalition leader Moaz Alkhatib said Iran was the real power in Damascus. Alkhatib had on Sunday offered to meet Assad's ceremonial deputy, Farouq al-Shara, for peace talks if the authorities released thousands of prisoners.
But in his interview, he said his proposal for talks with Shara had been rejected. He demanded the release of all women detainees by Sunday, or else his initiative "would have been broken", the BBC reported.
Underlining the deep regional divisions over the Syria conflict, Saudi Arabia, a key supporter of the Syrian rebels and a member of an "Islamic Quartet" formed by Mursi last August to try to broker a solution, did not attend the Syria crisis meeting in Cairo, diplomats said.
Saudi Crown Prince Salman told the summit the Syrian regime was "committing ugly crimes" against its people. He said the U.N. Security Council, which has so far been paralysed by Russian and Chinese opposition to sanctions, should act to "finalise the transition of power".
A communique drafted by OIC foreign ministers and seen by Reuters blames Assad's government for most of the slaughter and urges it to open talks on a political transition.
Diplomats said Iran had objected to the wording and it might be toned down to spread responsibility more evenly.
Iraqi Foreign Minister Hoshiyar Zebari said the statement had to be adopted by consensus and would stress the need for dialogue and a political solution.
The draft text also urged the opposition to speed up the creation of a transitional government "to be ready to assume responsibility in full until the completion of the desired political change process".
Without mentioning Assad, it says: "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..."
SPOTLIGHT ON MURSI
Mursi, a member of the Muslim Brotherhood, sought to project his country as the leader of the Islamic world in his speech, seven months after becoming Egypt's first democratically elected head of state.
He told the assembled kings, presidents and prime ministers that the "glorious Jan. 25 revolution" that toppled Egypt's autocrat Hosni Mubarak in 2011 "forms the cornerstone in the launching of this nation to new horizons of progress".
Egypt is taking over the OIC chair at a time of upheaval in the Arab world and sectarian tension between the main branches of Islam. Mursi is also grappling with sustained protests at home by liberal and leftist opponents who accuse him of seeking to monopolise power.
On Tuesday, he embraced Ahmadinejad and gave him a red-carpet airport welcome, but his foreign minister hastened to assure Gulf Arab states that Egypt would not sacrifice their security in opening to Tehran.
Syria was not present at the Islamic summit after being suspended from the OIC last August. The Syrian opposition said it had not received an invitation and would not be attending. (Additional reporting by Tom Perry, Marwa Awad and Asma Alsharif in Cairo, Khaled Yacoub Oweis in Amman and Tarek Amara in Tunis; Editing by Jon Hemming)