* OIC foreign ministers adopt Syria resolution -source
* Organisation of Islamic Cooperation summit starts Tuesday
* Iran's opposition illustrates sectarian divisions
By Asma Alsharif
JEDDAH, Aug 13 (Reuters) - Foreign ministers at a meeting of the Organisation of Islamic Cooperation (OIC) agreed on Monday to suspend Syria from the international body, an OIC source said, further isolating President Bashar al-Assad.
"The session just ended. The ministers adopted the resolutions, including the suspension of Syria," the source told Reuters.
The move by the OIC, a body comprising 56 member states plus the Palestinian Authority that aims to represent Muslim interests on the world stage, is its response to Assad's suppression of a 17-month uprising.
It will have more symbolic than practical implications for the Assad government which has never put emphasis on religion and which will continue to enjoy support from Iran which opposed the decision to suspend Syria at the OIC.
"By suspending membership, this does not mean that you are moving toward resolving an issue. This means that you are erasing the issue. We want to really resolve the issue," Iranian Foreign Minister Ali Akbar Salehi told reporters before the meeting in Jeddah, Saudi Arabia.
The ministers were holding preparatory talks before a two-day OIC summit in Mecca starting on Tuesday, which was called by Saudi Arabia's King Abdullah earlier this month.
The formal decision on Syria, which notionally requires a two-thirds majority, meaning that Iran alone will not be able to defeat the motion, will be taken by OIC leaders and announced on Wednesday, an OIC diplomat said.
Salehi's comments pointed towards a likely diplomatic showdown in Mecca between Sunni Muslim states, including Saudi Arabia, that have declared support for Assad's opponents, and Shi'ite Muslim Iran - a reflection of heightened sectarian tensions across the region.
Iranian President Mahmoud Ahmadinejad arrived in Mecca on Monday echoing King Abdullah's call for the summit to increase Muslim unity, saying before his departure that it was a chance for Tehran's views to be "explained transparently".
However, Iran has also pushed for the summit to address the continued uprising in Bahrain, where some Saudi troops went last year at the invitation of the Sunni monarchy to help quell mass protests by the tiny island state's Shi'ite majority.
King Abdullah's decision to invite Ahmadinejad drew rare criticism in Saudi-owned media, with an editorial in the kingdom's edition of pan-Arab daily al-Hayat on Monday saying it would "add only schism and division to the summit".
Saudi Arabia, worried that the Syria crisis will further inflame sectarian violence in Bahrain and other countries with large Shi'ite communities, has called for the Syrian people to be "enabled to protect themselves" if the world powers cannot protect them.
Iran, which denies accusations it has provided material for Assad's suppression of the uprising, has criticised countries in the Middle East and the West for supporting the rebels.
Salehi said on Sunday Iran was opposed to any internationally enforced no-fly zone over Syria, which Syrian rebels have called for to curb the Assad's air power.
"We are against any foreign interference of any kind in Syria, including a no fly zone," he said.