Key Points:

• NATO warns Russia 'must stop' air violations on eastern flank .
• "Russia bears full responsibility for these actions, which are escalatory, risk miscalculation and endanger lives.
• They must stop," NATO's 32 member states said in a statement .
• Estonia convened emergency consultations under Article 4 of NATO's founding treaty after armed Russian fighter jets violated its airspace for some 12 minutes on Friday .