The Saudi monarch \"sent a written letter to President Mahmoud Ahmadinejad inviting him to attend the extraordinary Islamic solidarity meeting which will be held in Mecca\" in mid-August, SPA reported. Tensions have been running high between the Sunni-dominated kingdom and Shiite Iran as both regional powers had taken opposite stances on the uprisings in Bahrain and Syria. Iran had voiced support to a Shiite-led uprising in Bahrain which Saudi Arabia had sent troops to crush last year. In Syria, the kingdom had called for arming rebels against the regime of President Bashar al-Assad -- who belongs to the Alawite minority, an off-shoot of Shiite Islam -- while Iran has been repeatedly accused of sending military aid to the Syrian government. Tehran has denied the claims. Saudi Arabia last month called for the summit in a bid at \"unifying the ranks\" of Muslims. Saudi Arabia hosts the headquarters of the 57-member pan-Muslim body -- the Organisation of Islamic Cooperation which is based in the Red Sea city of Jeddah.