n Wednesday, the North Atlantic Treaty Organisation, NATO, demanded Syria end what it called aggreesive acts against ally Turkey.

But the invocation of Article 4, rather than Article 5, of the NATO charter may show the limits of NATO's support of Ankara.

Article 4 of the organisation's charter calls on a "consultation" when an ally nation feels its sovereignity has been threatened, whereas Article 5 committs member states to defend another member.

Al Jazeera's Jacky Rowland reports from Brussels.