The leaders of all 28 member states of the European Union endorsed a statement on Monday "condemning" Turkey's military assault on Kurdish forces in northeastern Syria, warning that it will seriously undermine the stability of the region, cause extensive civilian suffering and potentially lead to the resurgence of ISIS.

Why it matters: Turkey is a key EU partner and a member of NATO. The European Council is calling on all member states to "immediately halt arms exports" to Turkey — a step that France and Germany have already taken — and will meet later this week to coordinate a further response.

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