Valmiki Ramayana Aranya Kanda Sarga 18 Shloka 21

इति this, उक्तः instructed, महाबलः powerful, लक्ष्मणः Lakshmana, क्रुद्धः being angry, रामस्य Rama's, पार्श्वतः by the side, खङ्गम् sword, उद्धृत्य having lifted, तस्याः her, कर्णनासम् ears and nose, चिच्छेद cut off.

Thus instructed (by Rama), powerful Lakshmana took position by the side of Rama, angrily lifted the sword and cut off her nose and ears.