In a move raising the potential threat of a Russia-NATO conflict, Russia says it will deploy long-range air defence missiles to its base in Syria and destroy any target that may threaten its warplanes after the downing of its military jet by Turkey.

Leaders of Muslim countries are expected to suspend Syria's membership of the Organisation of Islamic Cooperation at a summit in Mecca, despite the vocal objections of President Bashar al-Assad's main ally Iran.

Syria was hit by a third lethal car bombing as UN teams readied for a government-led humanitarian mission and to work to launch a monitoring operation to end a year of bloodshed.