Five more countries are withdrawing their monitors from an Arab League observer mission to Syria.
Saudi Arabia has already done so. The others are Bahrain, Kuwait, Oman, Qatar and the UAE.
The Gulf Co-operation Council also called on the UN Security Council to put new pressure on Damascus to end a violent crackdown against protests.
It came after Syria rejected an Arab League plan for President Bashar al-Assad to step down and hold elections.
Foreign Minister Walid Muallem said some Arab states had joined a foreign conspiracy to destabilise the country.
He said some regional powers were "internationalising" the situation in Syria by asking the UN Security Council to take action against Damascus.
Syria has long held that a foreign conspiracy backing armed groups is behind the unrest.